- Thread starter
- #21
I put a new "OEM" gas cap on it from Ebay a while ago. I'm a little suspicious of it since it doesn't have a very good click to it so I'm going to Toyota to get a new one.
Dies When Hot (1 Viewer)
- Thread starter Dan Porter
- Start date
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- Thread starter
- #22
I'm not getting any codes, is there any way to check whether charcoal canister is bad? Other than the expense, it looks like a rather easy fix.
JohnnyUtah2
SILVER Star
I didn’t have any CEL or codes. My symptoms were fuel smells in the cabin, and engine shut down during high ambient temperatures.
I replaced my charcoal canister with a Duralast/AC delco canister (which worked well) and then replaced that one with an oem 4.7 liter V8 Toyota Tundra canister.
It is possible to remove and replace the old charcoal, but it requires some effort and modifications to the original unit.
2001LC
SILVER Star
"strong chemical smell"
Likely the smell of old stall gas. Like gasoline left in a can for decades (putrefied). Good clue CC is loaded with old raw fuel and has been for a long time, is that strange smell. Saturated Charcoal Canisters (CC), just get worse with use. Heat like from OAT, engine & AT heat, trapped exhaust heat, radiant road heat, etc.. Results in expansion making condition worse.
At some point raw fuel enters CC. Either overfilling gas tank (03-07), engine run very hot for long time heating fuel (expanding). Drove up hill after topping fuel tank, on hot day, shanking full fuel tank on rocky road driving uphill, ect. Once raw fuel gets in CC, it staurates charcoal. The saturated charcoal then, can't keep up vapor flow and just keeps loading up. This result in excessive pressure in EVAP. Pressure = heat!
Correct issue that started CC staurating and then replace the CC. I use only OEM CC, based on the vehicle VIN#. In 06-07 I also replace the CC filter which is sold seperate.
If CC contaminated. It will be heavier than the new OEM one you install.
I've yet to see a DTC for bad CC.
Could OP remove charcoal canister and probably get a wiff of that old gas smell if he tested it?
What about removing the lines to the canister when the vehicle is experiencing the issue? If the issue goes away could that be a means of troubleshooting before replacing the CC?
Long thread but it’s a great read
forum.ih8mud.com
Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen?
DANGEROUS GAS PRESSURE BUILD UP IN GAS TANK! Why? What's going on? How can we fix this? Edited 3/15/25: Since first posting this thread. I've corrected many boiling fuel. By working in this order: Coolant system if first on the list, must be operating as designed. Which radiator fins cleaning...
forum.ih8mud.com
2001LC
SILVER Star
I think he got a wiff.
First time I got a wiff, was while engine running. I was sitting a red light in an 05LC, 85f -90f OAT. RPM's fluating, engine barely running. Putrid smell coming in cabin.
Come to find out. This 05LC Owner, regularly fill gas tank passed fuel pump handle auto shut-off. They first had issue (fuel boiling) in summer heat, climbing mountain passes. I found and correct many tune and coolant system issue. Which help issues of fuel boiling and stalls, but did not total correct. Condition worsen over the next year. To the point, just short drive, fuel vapors could be seen coming from gas cap area.
Remove CC and if smells bad, R&R. Old will be heavier than a new CC.
But removing lines and starting, IDK! Engine may have difficulty running, with lins off.
Guy in video, could have done this test, without dismounting canister from vehicle.
The FSM has a series of pressure vacuum and air flow test.
But if that bad smell is smelt, like very old gas. Save time, just replace the CC.
Last edited:
I also have a 2006 LX and I've been dealing with this exact issue every summer since I bought the vehicle five years ago with 150,000 miles on it. The LX drives great all year but at least 2 - 4 times every summer, when the weather here in Las Vegas gets near 100F and higher, and I've been driving around town in the hot afternoon sun (3pm - 6pm), and I come to an idle (ie. engine is NOT under load), the engine will occasionally start to stumble and then stall. The LX is not overheating and there are no error codes, but I then have to wait between 10 - 30 minutes for the fuel to cool down before the engine will turn over, and then start back up and run without any problem.
A couple of summers ago, after it had happened at least a half dozen times over the prior couple of years, it finally did throw a CEL and I had to replace a catalytic converter. Shortly after replacing the cat, it happened again when I pulled up to a stoplight in the late afternoon sun, in 100F weather, after I had been running errands around town. I shut everything down and pushed my LX to the side of the road, as I often do when this happens, but this time there was a strange sound coming near the gas tank so I removed the fuel cap and it sounded like the fuel was boiling. Even though the engine had been shut down for several minutes, I could see fuel shooting across the inside of the filler neck.
The stumble and stall in hot afternoon weather when at idle (not under load) after having been driving around in the hot weather, has happened to me at least a dozen times in the past 5 years, and it's ONLY ever happened during the summer, ONLY after I've been driving it around in the late afternoon sun (3pm - 6pm), and ONLY after I come to an idle and the engine NOT under load. Last summer, for the first time, it happened on a highway when I was going 60 mph; however, the weather was still near 100F, it was late afternoon, I had just climbed a couple of thousand feet in elevation, and I had just started coasting downhill (ie. engine NOT under load).
I've spoken with a half dozen or more mechanics and read countless forums over the years, but unfortunately, no one has been able to provide a clear diagnosis and solution to the issue. I think @OEMGUY0720 may be on the right track with insulating the fuel lines as I believe the core issue may be the fuel overheating, boiling, etc. I'm not confident it's an issue with the fuel filter, fuel pump, charcoal canister, fuel cap, radiator, water pump, MAF sensor, spark plugs, coils, or any of the other myriad of components suggested by commenters with the best of intentions.
After my 2006 LX stalled last year while coasting on the highway in hot weather (after having been under heavy load), I decided that the hot weather AND the engine NOT being under load may be the key factors (?), so now, whenever I'm idling at a stoplight in the hot afternoon sun during the peak of summer (ie. now), I put my LX in neutral and keep the engine under load (rpms between 1,200 - 1,500). I haven't had it stall yet this summer.
Maybe these experiences provide more clues to the more experienced mechanics on this site to come up with a rock-solid diagnosis and solution?
A couple of summers ago, after it had happened at least a half dozen times over the prior couple of years, it finally did throw a CEL and I had to replace a catalytic converter. Shortly after replacing the cat, it happened again when I pulled up to a stoplight in the late afternoon sun, in 100F weather, after I had been running errands around town. I shut everything down and pushed my LX to the side of the road, as I often do when this happens, but this time there was a strange sound coming near the gas tank so I removed the fuel cap and it sounded like the fuel was boiling. Even though the engine had been shut down for several minutes, I could see fuel shooting across the inside of the filler neck.
The stumble and stall in hot afternoon weather when at idle (not under load) after having been driving around in the hot weather, has happened to me at least a dozen times in the past 5 years, and it's ONLY ever happened during the summer, ONLY after I've been driving it around in the late afternoon sun (3pm - 6pm), and ONLY after I come to an idle and the engine NOT under load. Last summer, for the first time, it happened on a highway when I was going 60 mph; however, the weather was still near 100F, it was late afternoon, I had just climbed a couple of thousand feet in elevation, and I had just started coasting downhill (ie. engine NOT under load).
I've spoken with a half dozen or more mechanics and read countless forums over the years, but unfortunately, no one has been able to provide a clear diagnosis and solution to the issue. I think @OEMGUY0720 may be on the right track with insulating the fuel lines as I believe the core issue may be the fuel overheating, boiling, etc. I'm not confident it's an issue with the fuel filter, fuel pump, charcoal canister, fuel cap, radiator, water pump, MAF sensor, spark plugs, coils, or any of the other myriad of components suggested by commenters with the best of intentions.
After my 2006 LX stalled last year while coasting on the highway in hot weather (after having been under heavy load), I decided that the hot weather AND the engine NOT being under load may be the key factors (?), so now, whenever I'm idling at a stoplight in the hot afternoon sun during the peak of summer (ie. now), I put my LX in neutral and keep the engine under load (rpms between 1,200 - 1,500). I haven't had it stall yet this summer.
Maybe these experiences provide more clues to the more experienced mechanics on this site to come up with a rock-solid diagnosis and solution?
2001LC
SILVER Star
Anything done to reduce fuel heat is a good thing, no doubt!
But keep in mind. Off-the-showroom floor, a new 100 series did not boil fuel, rough idle or stall. Had they, we have countless service history of these boiling fuel, stall and rough idling events.
The one exception I've seen. Is the the 06-07 fuel pump. It is a know issue:
It was a new 06 here in Colo, that from mile 1 to 100K miles. keep going in for a "reported" vapor-lock. Almost always record as, by a statement from customer happening at Eisenhower tunnel. It had gone back into shop, repeatedly for diagnostic including fuel pump/pressure test. Shop foreman, tech and ser mgr. All climb in a drove up I-70 from Denver to Eisenhower, with tech stream hook-up. Still they couldn't find the cause of the issue. This went on for years. Finally after a T-belt job and a report of yet another vapor lock afterwards. Someone in the Shop (Dealership) decided to replace the fuel pump. Issue was finally cleared. Not one report of a stall over next 100K miles. This was never a vapor lock, it was fuel starvation.
Note: Eisenhower, is about about 5,000 ascent up from Denver the mile high city. With a rather long step climb, before entering from either direction. This requires driving in high RPM to climb the pass
Do you wrench?
Based on your driving history statements, you've multiple issue!
Just to be clear: When we say: "engine under load". This is when transmission is in gear (D, 1, 2 3 or 4), and we increase RPM, with foot on the brake. Can also be, referring to accelerating like when passing, getting on HWY, climb a hill/pass, towing, etc..
You've stated different driving condition and one repair:
"Shortly after replacing the cat"
CAT's go bad for a reason. What was the reason? What was done to correct?
Do you sit parked, idling with AC on?
You say "not overheating".
When stopped at a light in D, idling, AC on in summer heat & sun. What is the engine coolant temp (ECT)?
Is ECT increasing, while at light stopped? From and to what temp? Does ECT drop once you start driving, from what to what?
Note: We must read ECT through tech stream, not the dash water temp gauge.
"the engine will occasionally start to stumble and then stall" "when I pulled up to a stoplight in the late afternoon sun, in 100F weather, after I had been running errands around town."
This is somewhat classic of engine running to hot in need of a tune. Even more so, if contaminated/clogged Charcoal Canister (CC). A clogged CC alone will cause this.
"I'm idling at a stoplight in the hot afternoon sun during the peak of summer (ie. now), I put my LX in neutral and keep the engine under load (rpms between 1,200 - 1,500). I haven't had it stall yet this summer."
Shifting to N, increasing RPM, is not under load.
Having to do this, to keep engine running. Is classic of a clogged Charcoal Canister. It could, also be signs of a poorly tuned engine or both.
Additionally we see "misfires" act like this. Misfire is almost always from one or more coils (COP). We test for this in Tech Stream, by watching as we put "engine under load". Foot on brake, AT in D as we raise RPMs slowly. Note: There is a glitch in tech stream. In which misfire disappears under load. There's a video around on this and how to spot the misfire.
" I had just climbed a couple of thousand feet in elevation, and I had just started coasting downhill (ie. engine NOT under load)."
This is classic of a bad fuel pump in the 06-07 100 series. We replace fuel pump and fuel filter, which corrects the issue.
"I'm not confident it's an issue with the fuel filter, fuel pump, charcoal canister, fuel cap, radiator, water pump, MAF sensor, spark plugs, coils, or any of the other myriad of components suggested by commenters with the best of intentions.
You don't give any reference, to why your confident? All and more, need to be in proper working order.
I'll say with some confidence. Your issue is correctable. If you've a heavey (fully built rig), shielding will help. The heavies, have large metal front bumpers retaining more heat than stock and blocking air flow. They also have block air flow, trapping heat with the under body armor. The heat, gets directed along fuel line to gas tank. But even these can be mostly corrected, without shielding. But for the extreme conditions off road in build rigs. In slow, high RPM, long high altitude climbs over rocky passess. That added shield helps for sure. But even those, must well tuned (all system in spec).
In addition to fuel pump and well tuned:
Radiator fins need cleaning! Alert Alert Alert
I've a 06LC w/192K I just bought. In reading history I found PO complained of engine temp raising when both front and rear AC on. Toyota Dealership diagnosed with clogged radiator fins. Recommended new OEM radiator, $600 for the US spec Radaitor plus coolant and labor. They should have added...
forum.ih8mud.com
This is 06-07 mod I do, for the S.A.I. system. At some point, all S.A.I. pump filter fail. Toyota believes moisture "may" play a roll in when.
S.A.I. Filter Modification, in VVT engines. To prevent its failure! Alert Alert!
We've a $2.00 part in the S.A.I. (secondary air injection) system of the VVT engine, that is taking-out ~$7,000.00 $15,000 $25,000 (inflation) in parts. WOW! I've a very easy and cheap WORK AROUND. You are going to love this ;) This thread is dedicated to the 4.7L 2UZ-fe VVT engine, in the...
forum.ih8mud.com
Eyedaho
SILVER Star
There's also this aspect regarding the timing of reported fuel boiling issues in 100 series:Anything done to reduce fuel heat is a good thing, no doubt!
But keep in mind. Off-the-showroom floor, a new 100 series did not boil fuel, rough idle or stall. Had they, we have countless service history of these boiling fuel, stall and rough idling events.
The one exception I've seen. Is the the 06-07 fuel pump. It is a know issue:
It was a new 06 here in Colo, that from mile 1 to 100K miles. keep going in for a "reported" vapor-lock. Almost always record as, by a statement from customer happening at Eisenhower tunnel. It had gone back into shop, repeatedly for diagnostic including fuel pump/pressure test. Shop foreman, tech and ser mgr. All climb in a drove up I-70 from Denver to Eisenhower, with tech stream hook-up. Still they couldn't find the cause of the issue. This went on for years. Finally after a T-belt job and a report of yet another vapor lock afterwards. Someone in the Shop (Dealership) decided to replace the fuel pump. Issue was finally cleared. Not one report of a stall over next 100K miles. This was never a vapor lock, it was fuel starvation.
Note: Eisenhower, is about about 5,000 ascent up from Denver the mile high city. With a rather long step climb, before entering from either direction. This requires driving in high RPM to climb the pass
Do you wrench?
Based on your driving history statements, you've multiple issue!
Just to be clear: When we say: "engine under load". This is when transmission is in gear (D, 1, 2 3 or 4), and we increase RPM, with foot on the brake. Can also be, referring to accelerating like when passing, getting on HWY, climb a hill/pass, towing, etc..
You've stated different driving condition and one repair:
"Shortly after replacing the cat"
CAT's go bad for a reason. What was the reason? What was done to correct?
Do you sit parked, idling with AC on?
You say "not overheating".
When stopped at a light in D, idling, AC on in summer heat & sun. What is the engine coolant temp (ECT)?
Is ECT increasing, while at light stopped? From and to what temp? Does ECT drop once you start driving, from what to what?
Note: We must read ECT through tech stream, not the dash water temp gauge.
"the engine will occasionally start to stumble and then stall" "when I pulled up to a stoplight in the late afternoon sun, in 100F weather, after I had been running errands around town."
This is somewhat classic of engine running to hot in need of a tune. Even more so, if contaminated/clogged Charcoal Canister (CC). A clogged CC alone will cause this.
"I'm idling at a stoplight in the hot afternoon sun during the peak of summer (ie. now), I put my LX in neutral and keep the engine under load (rpms between 1,200 - 1,500). I haven't had it stall yet this summer."
Shifting to N, increasing RPM, is not under load.
Having to do this, to keep engine running. Is classic of a clogged Charcoal Canister. It could, also be signs of a poorly tuned engine or both.
Additionally we see "misfires" act like this. Misfire is almost always from one or more coils (COP). We test for this in Tech Stream, by watching as we put "engine under load". Foot on brake, AT in D as we raise RPMs slowly. Note: There is a glitch in tech stream. In which misfire disappears under load. There's a video around on this and how to spot the misfire.
" I had just climbed a couple of thousand feet in elevation, and I had just started coasting downhill (ie. engine NOT under load)."
This is classic of a bad fuel pump in the 06-07 100 series. We replace fuel pump and fuel filter, which corrects the issue.
"I'm not confident it's an issue with the fuel filter, fuel pump, charcoal canister, fuel cap, radiator, water pump, MAF sensor, spark plugs, coils, or any of the other myriad of components suggested by commenters with the best of intentions.
You don't give any reference, to why your confident? All and more, need to be in proper working order.
I'll say with some confidence. Your issue is correctable. If you've a heavey (fully built rig), shielding will help. The heavies, have large metal front bumpers retaining more heat than stock and blocking air flow. They also have block air flow, trapping heat with the under body armor. The heat, gets directed along fuel line to gas tank. But even these can be mostly corrected, without shielding. But for the extreme conditions off road in build rigs. In slow, high RPM, long high altitude climbs over rocky passess. That added shield helps for sure. But even those, must well tuned (all system in spec).
In addition to fuel pump and well tuned:
Radiator fins need cleaning! Alert Alert Alert
I've a 06LC w/192K I just bought. In reading history I found PO complained of engine temp raising when both front and rear AC on. Toyota Dealership diagnosed with clogged radiator fins. Recommended new OEM radiator, $600 for the US spec Radaitor plus coolant and labor. They should have added...
This is 06-07 mod I do, for the S.A.I. system. At some point, all S.A.I. pump filter fail. Toyota believes moisture "may" play a roll in when.
S.A.I. Filter Modification, in VVT engines. To prevent its failure! Alert Alert!
We've a $2.00 part in the S.A.I. (secondary air injection) system of the VVT engine, that is taking-out ~$7,000.00 $15,000 $25,000 (inflation) in parts. WOW! I've a very easy and cheap WORK AROUND. You are going to love this ;) This thread is dedicated to the 4.7L 2UZ-fe VVT engine, in the...
ETA source:
@2001LC I truly appreciate all your input, experience, and expertise with this issue. It's been a huge thorn in my side for the past several years. If you are saying the 06-07 fuel pump is a known issue then I will add it to the top of my list of parts to replace.Anything done to reduce fuel heat is a good thing, no doubt!
But keep in mind. Off-the-showroom floor, a new 100 series did not boil fuel, rough idle or stall. Had they, we have countless service history of these boiling fuel, stall and rough idling events.
The one exception I've seen. Is the the 06-07 fuel pump. It is a know issue:
It was a new 06 here in Colo, that from mile 1 to 100K miles. keep going in for a "reported" vapor-lock. Almost always record as, by a statement from customer happening at Eisenhower tunnel. It had gone back into shop, repeatedly for diagnostic including fuel pump/pressure test. Shop foreman, tech and ser mgr. All climb in a drove up I-70 from Denver to Eisenhower, with tech stream hook-up. Still they couldn't find the cause of the issue. This went on for years. Finally after a T-belt job and a report of yet another vapor lock afterwards. Someone in the Shop (Dealership) decided to replace the fuel pump. Issue was finally cleared. Not one report of a stall over next 100K miles. This was never a vapor lock, it was fuel starvation.
Note: Eisenhower, is about about 5,000 ascent up from Denver the mile high city. With a rather long step climb, before entering from either direction. This requires driving in high RPM to climb the pass
Do you wrench?
Based on your driving history statements, you've multiple issue!
Just to be clear: When we say: "engine under load". This is when transmission is in gear (D, 1, 2 3 or 4), and we increase RPM, with foot on the brake. Can also be, referring to accelerating like when passing, getting on HWY, climb a hill/pass, towing, etc..
You've stated different driving condition and one repair:
"Shortly after replacing the cat"
CAT's go bad for a reason. What was the reason? What was done to correct?
Do you sit parked, idling with AC on?
You say "not overheating".
When stopped at a light in D, idling, AC on in summer heat & sun. What is the engine coolant temp (ECT)?
Is ECT increasing, while at light stopped? From and to what temp? Does ECT drop once you start driving, from what to what?
Note: We must read ECT through tech stream, not the dash water temp gauge.
"the engine will occasionally start to stumble and then stall" "when I pulled up to a stoplight in the late afternoon sun, in 100F weather, after I had been running errands around town."
This is somewhat classic of engine running to hot in need of a tune. Even more so, if contaminated/clogged Charcoal Canister (CC). A clogged CC alone will cause this.
"I'm idling at a stoplight in the hot afternoon sun during the peak of summer (ie. now), I put my LX in neutral and keep the engine under load (rpms between 1,200 - 1,500). I haven't had it stall yet this summer."
Shifting to N, increasing RPM, is not under load.
Having to do this, to keep engine running. Is classic of a clogged Charcoal Canister. It could, also be signs of a poorly tuned engine or both.
Additionally we see "misfires" act like this. Misfire is almost always from one or more coils (COP). We test for this in Tech Stream, by watching as we put "engine under load". Foot on brake, AT in D as we raise RPMs slowly. Note: There is a glitch in tech stream. In which misfire disappears under load. There's a video around on this and how to spot the misfire.
" I had just climbed a couple of thousand feet in elevation, and I had just started coasting downhill (ie. engine NOT under load)."
This is classic of a bad fuel pump in the 06-07 100 series. We replace fuel pump and fuel filter, which corrects the issue.
"I'm not confident it's an issue with the fuel filter, fuel pump, charcoal canister, fuel cap, radiator, water pump, MAF sensor, spark plugs, coils, or any of the other myriad of components suggested by commenters with the best of intentions.
You don't give any reference, to why your confident? All and more, need to be in proper working order.
I'll say with some confidence. Your issue is correctable. If you've a heavey (fully built rig), shielding will help. The heavies, have large metal front bumpers retaining more heat than stock and blocking air flow. They also have block air flow, trapping heat with the under body armor. The heat, gets directed along fuel line to gas tank. But even these can be mostly corrected, without shielding. But for the extreme conditions off road in build rigs. In slow, high RPM, long high altitude climbs over rocky passess. That added shield helps for sure. But even those, must well tuned (all system in spec).
In addition to fuel pump and well tuned:
Radiator fins need cleaning! Alert Alert Alert
I've a 06LC w/192K I just bought. In reading history I found PO complained of engine temp raising when both front and rear AC on. Toyota Dealership diagnosed with clogged radiator fins. Recommended new OEM radiator, $600 for the US spec Radaitor plus coolant and labor. They should have added...
This is 06-07 mod I do, for the S.A.I. system. At some point, all S.A.I. pump filter fail. Toyota believes moisture "may" play a roll in when.
S.A.I. Filter Modification, in VVT engines. To prevent its failure! Alert Alert!
We've a $2.00 part in the S.A.I. (secondary air injection) system of the VVT engine, that is taking-out ~$7,000.00 $15,000 $25,000 (inflation) in parts. WOW! I've a very easy and cheap WORK AROUND. You are going to love this ;) This thread is dedicated to the 4.7L 2UZ-fe VVT engine, in the...
My 2006 LX is completely stock other than some KO2 tires and Tundra wheels that I put on it about a year and a half after I bought it. I don't wheel it but I do take it on some dirt roads when camping. I purchased it in May 2019 with 153,000 miles from the original owner in San Diego, CA who had babied it, always kept it dealer-maintained, never towed anything (or even took it off-road), and even used a car cover on it. It has been my daily driver since I bought it and I believe that first summer that I had it in Vegas, it may have only stumbled and stalled one or two times. However, at that time, when I wasn't driving it, I kept it parked in my garage at home or in a garage at work, so it rarely sat outside in the hot afternoon sun. Needless to say, I was very confused the first few times that it happened
Unfortunately, it has stumbled and stalled at least 2 - 4 times every summer since I bought it; and every time it has stumbled and stalled, the following conditions have been present:
- Summertime with the weather nearing or above 100F.
- It's late in the afternoon (3pm - 6pm) during peak daytime heat
- I was driving the vehicle on the freeway or around town in the hot afternoon sun (min. half hour or longer)
- I had recently taken my foot off the gas pedal and was coasting or had come to an idle.
The engine has never stumbled and stalled without all four of these conditions being present.
I mentioned that last summer I was driving through the Mojave Desert in the late afternoon heat when it stumbled and stalled after I had just climbed 2,000 feet and had crested a peak elevation of 4,700 ft; however, the four conditions above were also still present. Earlier that same trip, in much cooler weather and earlier in the day, I had driven over several other mountain passes including one with an elevation of 9,700 ft, and four that were above 6,000 ft., and the vehicle did not have any issues.
Since I bought the vehicle in 2019, the engine temperature gauge on my dash has never gone higher than halfway up. The engine seems to run great year-round other than the few sporadic stumbles and stalls in the summer, during peak afternoon heat, when my foot is not on the throttle.
After it had stumbled and stalled again a few times the second summer after I bought it, the CEL came on and it threw an error code that it wasn't reading correctly below the passenger side cat. I replaced the fuel filter with another OEM fuel filter and tried replacing both 02 sensors in hopes of an easier fix but neither job fixed the CEL and I had to replace the cat so that I could pass smog. I wish I knew what caused the cat to go bad. I figured it had something to do with the misfires and stalling since the CEL and error code came on right after the engine had stumbled and stalled for the 3rd or 4th time. Maybe boiling fuel was getting past the engine and down into the cat? I don't know. I didn't want to replace the cat without fixing the underlying issue but I took it to several mechanics and none of them could tell me what caused it to go bad. They all just said I needed to replace the cat. I told them that replacing the cat was not solving the real issue but they said that was all they could do.
No surprise, the stumbles and stalls have not stopped since I replaced the passenger side cat. This even resulted in another CEL last summer and me having to replace the drivers side cat. It's only a matter of time before it happens again if I can't get this sorted out.
In case it doesn't come across in my posts, this issue has been insanely frustrating for me.
2001LC
SILVER Star
First: If you'd like, we can talk on the phone. Just post your phone and a link to this page in the PM to me. You most likely, have multiple issues. I had bought an 07 with all issue you're having. Just to see what was causing and how to correct. I GF has been diving for ~4 yrs since I corrected all issues, without issues. It is the first one with the VVT S.A.I. mod, my test vehicle.
Yes 06-07 fuel pumps, are a known issue. But not all are bad. Very clear indication is: Hot day typically, full sun in the afternoon. Running engine at high RPM which runs fuel pump at higher speed. This is happens most often here in CO, ascending a pass, As we're in higher RPM for a prolonged period as we climb the pass. But there have been reports out of LV NV, of just passing. We drop RPM back, fuel speed/RPM also drops back, and engine stalls. BK1 & BK2 lean fuel condition. Replace fuel, has corrected this condition every time.
The CAT's both failing are a bad sign. It can be as simple a cause killing them. As prolonged idling. Which the OM (owners manual) warns do not and states 20 minutes. Personal, I don't idle more than 3 minutes. The exception is when servicing, sometime we must.
Unfortunately, the leaning cause of 06-07 both CAT failure. Is in the link I provided, in above post #29 S.A.I. mod. The filter in the S.A.I. pump fails, resulting in a long list os issues.
Fuel and fuel blend is (corn gas) is an issue. But more of and issues is flooding charcoal canister and or engine running hot. With a used vehicle, we've just don't know, if PO overfill gas tank (squeeze fueling pump handle adding more fuel, after auto shut off pump handle), Or did other things that are just the same as overfilling.
So very often I find coolant system low, rad cap or reservoir not working properly and most of all radiator fins clogged.
Your dash WATER TEMP (AKA engine coolant temp, aka ECT) gauge is a poor indicator of actual engine coolant temp. Since your having issues. I suggest you get a OBD device to watch ECT, fuel trims, CAT temp, AT fluid temps, ect. I use OBDmx, since its open software allows you choices. But there are many device let you watch tech stream and log data on your smartphone.
Here just a random picture of "DashBoard" I set up on my iphone, to watch on 06-07. They (06-07) gives use CAT temps and A/T 1 & A/T 2 fluid temps.
Yes 06-07 fuel pumps, are a known issue. But not all are bad. Very clear indication is: Hot day typically, full sun in the afternoon. Running engine at high RPM which runs fuel pump at higher speed. This is happens most often here in CO, ascending a pass, As we're in higher RPM for a prolonged period as we climb the pass. But there have been reports out of LV NV, of just passing. We drop RPM back, fuel speed/RPM also drops back, and engine stalls. BK1 & BK2 lean fuel condition. Replace fuel, has corrected this condition every time.
The CAT's both failing are a bad sign. It can be as simple a cause killing them. As prolonged idling. Which the OM (owners manual) warns do not and states 20 minutes. Personal, I don't idle more than 3 minutes. The exception is when servicing, sometime we must.
Unfortunately, the leaning cause of 06-07 both CAT failure. Is in the link I provided, in above post #29 S.A.I. mod. The filter in the S.A.I. pump fails, resulting in a long list os issues.
Fuel and fuel blend is (corn gas) is an issue. But more of and issues is flooding charcoal canister and or engine running hot. With a used vehicle, we've just don't know, if PO overfill gas tank (squeeze fueling pump handle adding more fuel, after auto shut off pump handle), Or did other things that are just the same as overfilling.
So very often I find coolant system low, rad cap or reservoir not working properly and most of all radiator fins clogged.
Your dash WATER TEMP (AKA engine coolant temp, aka ECT) gauge is a poor indicator of actual engine coolant temp. Since your having issues. I suggest you get a OBD device to watch ECT, fuel trims, CAT temp, AT fluid temps, ect. I use OBDmx, since its open software allows you choices. But there are many device let you watch tech stream and log data on your smartphone.
Here just a random picture of "DashBoard" I set up on my iphone, to watch on 06-07. They (06-07) gives use CAT temps and A/T 1 & A/T 2 fluid temps.
Thanks again for the continued insight. I've been trying to read through the entire S.A.I. mod thread this week but it is taking me some time. I'd also classify myself as a very novice mechanic, so I often have to read things multiple times and even then I don't always understand what i'm reading. It's amazing to me that Toyota hasn't provided a proper solution considering how common of an issue this is for many '06-'07 owners.
Regarding idling, I can't speak for the original owner but I'm the guy who doesn't like to use drive-thru's because I don't like idling vehicles. The most you'll see me idling is at a stoplight. I've been that way since long before I owned my LX. My wife is the opposite, she could idle all day and couldn't care less. However, she's only driven my LX maybe a couple dozen times in the 5 years that I've owned it and this issue has been going on since the first summer I bought it.
I've been using a cheap FiXD obd scanner for the past year or so but it doesn't show engine coolant temp. In just the past year, I have had the P0430 code (Bank 1 efficiency below threshold) a couple of times and also P0037 (Bank 1, sensor 2 heater control circuit low). When I first started having issues with the misfire, stalling and CEL, I believe the code was P0420 for bank 2 efficiency below threshold. Knock on wood, I haven't had a CEL for the past couple of months and I just did a scan this morning with no issues reported. I have noticed in the past year or so that my fuel economy seems to have dropped another 1 - 2 mpg, so maybe that has something to do with the S.A.I. and the fuel/air ratio?
Coincidentally, just a couple weeks ago my radiator sprung a leak. I had just driven across town in 110F weather and pulled into my garage. As soon as I got out I could smell the coolant - I looked under my car and it was coming out in a steady stream. I installed a new OEM radiator last week and put in the Toyota super long life (pink) coolant. (Thank you Lexus of North Scottsdale for offering a better deal than all local and online Lexus and Toyota dealers). I've been driving it daily this week and the engine and coolant temp seem fine (my only reference is the dash gauge) but now when I move the AC to its highest setting I can hear a low hum, which I don't ever recall hearing. The sound is only noticeable when the AC is on the highest setting - just a low, constant humming sound. I'm going to switch out the cabin air filter this week and see if that has something to do with it.
I may PM you after I get through the S.A.I. thread and have more time to focus on this fuel delivery & exhaust issue.
I am new to the forum here and have a 2006 LX470 that has had the same issues in the summer 2-4 times per year. We are in the Central Valley CA and we can get days over 110 F. We bought it with 30k miles and this issue kept reoccurring. After numerous trips to dealership while under 100k miles they never seemed to find a definite cause. Plug coils were changed, Fuel Pump was never changed by dealer. Usually happens after freeway driving, then transition to stop and go at the lights. poor airflow, more heat. Truck starts serious rough idle and dash lights up like a Christmas tree. Park for 30 min or so, restart problem disappears. Super frustrating. Fresno Dealer never found definite cause and claimed we had a one of issue. Local mechanic changed charcoal canister, fuel pump, filler neck tube, and fuel cap with all OEM parts a few years ago and the problem went away. Last year when off roading up over an 8000' elevation pass with full load it happened again. outside temp was 100+ at the time. Parked, waited, started - hasn't happened since, but we also haven't had it in same conditions since. Truck is now over 330k miles and if there is anything to do to prevent this from happening again I would gladly take some advice. Sounds like it is not a one of situation in warm climates!
Thanks for sharing your experience @j3cub. Whenever I read about this issue, it almost always seems to be with a 2006 or 2007 LX, which is when they added the Variable Valve Timing (VVT-i) to the engine. Maybe that has something to do with the issue? It definitely seems to be a more common issue than Lexus or Toyota is willing to admit.
It's interesting that you had a mechanic change the charcoal canister, fuel pump, filler neck, and fuel cap, and then the issue went away for a few years, and the issue has only re-occurred at high elevation. I've been thinking for the past couple of years that it is an issue with the fuel system and your experience may give further evidence of that. I have yet to find a mechanic that can diagnose the root issue, but I still have a couple more mechanics in the Las Vegas area that I'm considering to attempt to diagnose it.
I will update this forum as soon as I have more info that may be of help.
It's interesting that you had a mechanic change the charcoal canister, fuel pump, filler neck, and fuel cap, and then the issue went away for a few years, and the issue has only re-occurred at high elevation. I've been thinking for the past couple of years that it is an issue with the fuel system and your experience may give further evidence of that. I have yet to find a mechanic that can diagnose the root issue, but I still have a couple more mechanics in the Las Vegas area that I'm considering to attempt to diagnose it.
I will update this forum as soon as I have more info that may be of help.
2001LC
SILVER Star
There are two issues with the VVTi.
1) Fuel pump was changed in the 06-07 100 series, to a smaller pump. This fuel pump has known issue. Whereas it spins slower in low speed mode, than should, under certain condition. This is when, resistance (heat) high in wiring and pump. This, result in a lean fuel mixture BK1 & BK2. After running in high speed (engine above ~3K RPM) as fuel pump switches low speed (when engine RPMs drop back to cruising ranges). As it, revert to low power/slow speed. Which is controlled by the ECU, via fuel pump resistor (reduces voltage, to pump).
We replace fuel & filer, and problem solved.
Slow or reduced fuel flow, can happen in any year, due to bad gas for one That is gas, from old fuel storage tanks, that have rust & water in them. Which weakens, fuel pumps and clogs sock & fuel filter. Old fuel pumps, even in the 98-05, do also weaken with time. Which also can reduce fuel flow & pressure. Watching fuel trims is a valuable tool, yielding clues. In diagnosing weak fuel pumps..
2) S.A.I system filter loss. Loss of this filter, will damage: SAI system, cylinder compression and CATs.
Number one cause of engine running hot. Is improperly maintain coolant system. Which number one issues i see, is radiator fins clogged and low coolant level. We must keep fins clean. by washing them.
We must keep coolant system properly maintained. i.e. clean fins, rad cap, thermostat, reservoir hose, coolant flushes and a good fan clutch.
3) We must also have good intake (air filter), no vacuum leaks and in general a well turn engine.
4) We must also consider AT fluid temp. If you transmission fluid is running hot. That heat bleeds off to AC condensor and engine radiator. Then everything down stream, runs hotter
5) Once all else as it should be, like day it came from factory. We then consider the charcoal canister replacement. Number one reason we see contaminated CC, in the 03-07. Overfilling gas tank. Fuel just to high in right condition, is same as overfilling. Think of fuel tanks fill neck, as an overfilled teapot. Fuel expands as it heat. Travels up the spot and pours into CC in the 03-07.
98-02 CC are not as susceptible to CC, to over filling. But they too, become contaminated. Faster, if all above not as it should be. But I've yet to need to replace one. Even at 400K miles.
If a build heavy rig, especially if it has a belly pan. Consider heat shield and air diverters.
1) Fuel pump was changed in the 06-07 100 series, to a smaller pump. This fuel pump has known issue. Whereas it spins slower in low speed mode, than should, under certain condition. This is when, resistance (heat) high in wiring and pump. This, result in a lean fuel mixture BK1 & BK2. After running in high speed (engine above ~3K RPM) as fuel pump switches low speed (when engine RPMs drop back to cruising ranges). As it, revert to low power/slow speed. Which is controlled by the ECU, via fuel pump resistor (reduces voltage, to pump).
We replace fuel & filer, and problem solved.
Slow or reduced fuel flow, can happen in any year, due to bad gas for one That is gas, from old fuel storage tanks, that have rust & water in them. Which weakens, fuel pumps and clogs sock & fuel filter. Old fuel pumps, even in the 98-05, do also weaken with time. Which also can reduce fuel flow & pressure. Watching fuel trims is a valuable tool, yielding clues. In diagnosing weak fuel pumps..
2) S.A.I system filter loss. Loss of this filter, will damage: SAI system, cylinder compression and CATs.
Number one cause of engine running hot. Is improperly maintain coolant system. Which number one issues i see, is radiator fins clogged and low coolant level. We must keep fins clean. by washing them.
We must keep coolant system properly maintained. i.e. clean fins, rad cap, thermostat, reservoir hose, coolant flushes and a good fan clutch.
3) We must also have good intake (air filter), no vacuum leaks and in general a well turn engine.
4) We must also consider AT fluid temp. If you transmission fluid is running hot. That heat bleeds off to AC condensor and engine radiator. Then everything down stream, runs hotter
5) Once all else as it should be, like day it came from factory. We then consider the charcoal canister replacement. Number one reason we see contaminated CC, in the 03-07. Overfilling gas tank. Fuel just to high in right condition, is same as overfilling. Think of fuel tanks fill neck, as an overfilled teapot. Fuel expands as it heat. Travels up the spot and pours into CC in the 03-07.
98-02 CC are not as susceptible to CC, to over filling. But they too, become contaminated. Faster, if all above not as it should be. But I've yet to need to replace one. Even at 400K miles.
If a build heavy rig, especially if it has a belly pan. Consider heat shield and air diverters.
Has anyone changed to a single speed or earlier model fuel pump with associated wiring adjustments? Although issue is infrequent it happens at very inopportune times. Family not Happy when waiting in 100+ weather for things to cool down.
@2001LC I finally got through reading several of your other threads going back several years, the Snowy resto, etc. Only took me a year to get to it.
Based on your descriptions, I'm about 98% certain the SAI filter under the manifold on my '06, is probably disintegrated and gone. I'll need to do that mod. I replaced both CATs maybe 2 or 3 years ago after the CEL gave me the 0430/0420 error codes, even though I was adamant with every mechanic that replacing the CATs wasn't fixing the underlying problem. Nonetheless, I needed to get it done so I could pass smog and renew registration since it is my DD.
Well, I had no CEL for the first year or so after replacing the CATs, and then after the first couple of engine stumble-and-stalls the next hot Vegas summer, the CEL came back on, and it has been coming on and off ever since. No surprise to me, but still frustrating as he**. I've been able to get it to pass smog the past 2 years by going on days when the CEL was off, but over the past 6 - 9 months, the CEL has been coming on and staying on more frequently and for longer periods. I doubt I'll be able to pass smog again next year without replacing the CATs again.
I also need to replace the fuel pump to hopefully fix the stumble & stall issue. As @j3cub asked above, do you know if it is possible to install the larger '05 or earlier fuel pump in the VVT-i engines?? If we replace the same smaller '06-'07 OEM fuel pump, how long can we expect it to last before its starts to fail again in hot afternoon weather when coming from high rpms to low?
Lastly, can you post a link to a thread showing the parts needed to replace the VVT-i fuel pump and how to do it? Do we need to replace the entire pump or just certain components of the pump? I know there are youtube videos out there and probably some other threads explaining how to do it, but I trust your first-hand experience. Thanks!!
Based on your descriptions, I'm about 98% certain the SAI filter under the manifold on my '06, is probably disintegrated and gone. I'll need to do that mod. I replaced both CATs maybe 2 or 3 years ago after the CEL gave me the 0430/0420 error codes, even though I was adamant with every mechanic that replacing the CATs wasn't fixing the underlying problem. Nonetheless, I needed to get it done so I could pass smog and renew registration since it is my DD.
Well, I had no CEL for the first year or so after replacing the CATs, and then after the first couple of engine stumble-and-stalls the next hot Vegas summer, the CEL came back on, and it has been coming on and off ever since. No surprise to me, but still frustrating as he**. I've been able to get it to pass smog the past 2 years by going on days when the CEL was off, but over the past 6 - 9 months, the CEL has been coming on and staying on more frequently and for longer periods. I doubt I'll be able to pass smog again next year without replacing the CATs again.
I also need to replace the fuel pump to hopefully fix the stumble & stall issue. As @j3cub asked above, do you know if it is possible to install the larger '05 or earlier fuel pump in the VVT-i engines?? If we replace the same smaller '06-'07 OEM fuel pump, how long can we expect it to last before its starts to fail again in hot afternoon weather when coming from high rpms to low?
Lastly, can you post a link to a thread showing the parts needed to replace the VVT-i fuel pump and how to do it? Do we need to replace the entire pump or just certain components of the pump? I know there are youtube videos out there and probably some other threads explaining how to do it, but I trust your first-hand experience. Thanks!!
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2001LC
SILVER Star
You're correct! We can't just replace CATs. We must correct root cause(s) of failure.
First I'd monitor engine (ECT & Fuel Trims) and automatic transmission fluid (ATF) temp. While driving on hot summer days. Then, do whatever is needed, to bring all in line.
Second I'd use my 6mm directional borescope, to inspect SAI filter. If filter out of sight, I'd MOD with replaceable filter.
Once ECT (engine coolant temp), Fuel trims and ATF, all running as they should. I'd replace the CATs. I'd use either OEM, or aftermarket bolt in type like Davico. making sure no leaks. I see many INDY shops install poorly, leaking everywhere it possible could. It is also advisable to replace A/F and O2 sensors, but not a must if they're not kicking off DTC (CEL).
I've never seen the need, as no replacement has even had issues.
I've replace many fuel pumps, 98-07. There's a ton of thread on how to in iH8mud. I was using the $100 Denso fuel pump in the VVT (06-07). But they're no longer available (Denso no longer manufactures. I do see some for sale online (could be old stock or boot leg)). Other alternative fuel pumps are noted in ih8mud. I just use OEM these days. Which OEM comes with cage & socket. I also replace the rubber grommet at bottom of fuel pump and the short hose at top of fuel pump.
In all i've replaced over past 10 years with Denso or Toyota Denso or the New OEM Toyota Aisin. I've never had one replacement give me trouble.
Note: I always replace, fuel tanks to pump assy seal. I also always, replace fuel filter (OEM) and it's green locking clip. When R&R fuel pump.
Also note. I see a lot of bad Charcoal Canister (CC) in the 03-07. Due to over filling fuel tank. Overfilling can be from: Adding fuel after auto pump handle shut off, filling on hot day with 54f fuel and parking on hot 130F sun soaked pavement (expansion), filling and then ascenting a pass (rocking pass is worst) Think of fuel tank as a teapot, the fill neck is the spot), overheating engine & ATF boiling fuel, boil fuel for any reason, etc.. A bad CC can result in low stubling RPM while at a stop light and stalls. More so on hot days.
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I am driving the 07 100 series and am dealing with some similar issues.
I have had the fuel issue that has been mentioned twice over the last couple of years. First time, had family in a fully loaded vacation cruiser going up US 395 in Calfiornia. Cruising speed was around 70. However, when I slowed to use a rest stop, air temp around 115, the engine stuttered and then wouldn't start. We waited about 30 minutes for things to cool down, it started, we got back to speed and had no issues for the rest of the trip and basically till last summer. Last summer, in 100+ degrees, was taking a friend up a trail, at very slow speed and we came to almost a stop and I had the same problem. I waited for about 15 minutes, it started but the problem kept coming back until I was able to increase the vehicle speed and since then it hasn't been an issue.
I have full undercarriage skid plates, with very little ventilation. The fuel line from the tank runs from the back to the front, trapped. I have experienced vapor lock on other vehicles in the past and I think that the fuel in the lines is vaporizing because of the lack of air flow, especially when the vehicle comes to a stop.
I haven't heard anyone suffer something similar in mild temps. I have heard of instances of this happening in vehicles that don't have skid plates.
When I get really motivated, I might drill a few holes in the skid plates to allow for better air flow as well as insulating the fuel line from the tank forward...or just go to cooler places in the summer--played in the dunes at Pismo for a weekend with no fuel issues.
I have had the fuel issue that has been mentioned twice over the last couple of years. First time, had family in a fully loaded vacation cruiser going up US 395 in Calfiornia. Cruising speed was around 70. However, when I slowed to use a rest stop, air temp around 115, the engine stuttered and then wouldn't start. We waited about 30 minutes for things to cool down, it started, we got back to speed and had no issues for the rest of the trip and basically till last summer. Last summer, in 100+ degrees, was taking a friend up a trail, at very slow speed and we came to almost a stop and I had the same problem. I waited for about 15 minutes, it started but the problem kept coming back until I was able to increase the vehicle speed and since then it hasn't been an issue.
I have full undercarriage skid plates, with very little ventilation. The fuel line from the tank runs from the back to the front, trapped. I have experienced vapor lock on other vehicles in the past and I think that the fuel in the lines is vaporizing because of the lack of air flow, especially when the vehicle comes to a stop.
I haven't heard anyone suffer something similar in mild temps. I have heard of instances of this happening in vehicles that don't have skid plates.
When I get really motivated, I might drill a few holes in the skid plates to allow for better air flow as well as insulating the fuel line from the tank forward...or just go to cooler places in the summer--played in the dunes at Pismo for a weekend with no fuel issues.
