Bad Hesitation (video included) where should I start? (1 Viewer)

[96LX]

I took the Cruiser on a ski trip last weekend. The trip totaled about 1300 miles, it was my first big trip with the truck (other then when I flew out to buy it and drive it back) and I could not stop thinking about how great this truck is. Hauling 5 guys, 5 snowboards, and all the gear for the weekend, it cruised at 80 mph comfortably. With o/d off it zipped up the mountain passes in third gear at 3000 rpm's effortlessly. At the higher elevations there was some moderate snow with some very strong gusts/ lots of blowing snow and the cruiser felt very planted and confident.

However, about 40 miles from home on the way back I felt one big lurch at about 65 mph when going up a small hill and I grew a bit concerned but I chalked it off as a bump in the road/ paranoia. When I got off the interstate I noticed it was idling at about 900 rpm and felt a little rough but I was home soon and didn't think much of it.

Today it is a different story, upon acceleration it hesitates/lurches wildly upon acceleration from a stop. I also felt a couple small lurches at highway speed as well.

There were two times where I admittedly used too much skinny pedal on a pass and it briefly downshifted to 2nd gear then right back up to 3rd. I don't think that would be enough to kill one of these transmissions right?

There are two threads that I can find that seem similar to this situation.

In this thread Acceleration hesitation the OP fixes the issue by finding and cleaning a clogged up EGR port and changing the spark plugs. However his issue was when the engine was hot. Mine is acting up badly when cold, and not as bad but still acting up when hot too.

And this thread https://forum.ih8mud.com/threads/new-fzj80-hesitation-at-low-rpms.899896/
without a conclusion from the OP.

As this is my DD, I need take a look at this ASAP after work. What do you think I should look at first? These two threads suggest cleaning the EGR, based on the video is that my best bet?

In this video I am slowly and smoothly depressing the accelerator. Please excuse the terribly quality, I took this video in desperation on my way to work this morning.

 

[Michael Hanson]

Hi, Did you check and make sure all the vacuum hoses are on and not cracked ? Look for simple things first . Any cracks in the throttle body to air cleaner rubber hoses ? Mike

 

[96LX]

Hi Mike,

I haven't had a chance to take a look under the hood yet. I'm hoping to collect ideas so I can get a jump on it after work. I will definetly take a look at the vacuum hoses, thank you for the suggestion.

Also I forgot to mention that I have recently replaced the plugs, wires, distributor and belts as PM. I also recently replaced the fuel filter and cut open the charcoal canister to inspect the valve and replace the charcoal recently as well.

 

[ajax1]

Vacuum lines, timing is set correct bolt didn't loosen did it? All plugs seated and plug wires seated fully down? Did you use oem plugs and wires? Main air hose to throttle body check for cracks in the accordion section

 

[96LX]

OK I have checked every hose that I can see, none of them look suspect. I have not checked if the plugs are seated but I changed the plugs wires and distributor cap and rotor all OEM almost 5,000 miles ago so I doubt they wouldv'e waited to unseat until now but I don't know that for sure.

I do not have a timing light available but I did just grab the distributor bracket firmly and tried to move it with no movement, also it looked to be in the middle of the adjustment slot. Possibly unrelated question, what is the timing supposed to be at for a supercharged 1FZ-FE?

1. INSPECT AND CLEAN FILTER IN EGR VACUUM MODULATOR
(a) Remove the cap and filter.
(b) Check the filter for contamination or damage.
(c) Using compressed air, clean the filter.
(d) Reinstall the filter and cap.

Did this and the filter was almost new looking, the PO must have changed it recently.

The next steps to inspect the modulator involve a vacuum gauge which I do not currently have.

19. INSPECT EGR VACUUM MODULATOR OPERATION
(a) Block ports P and R with your finger.
(b) Blow air into port Q, and check that the air passes through
to the air filter side freely.
(c) Start the engine, and maintain speed at 2,500 rpm.
(d) Repeat the above test. Check that there is a strong resistance
to air flow.
If operation is not as specified, replace the EGR vacuum modulator.

I did these steps and everything seemed good, although its hard to tell what the strong resistance to air flow is with the air gun.


4. INSPECT TVV OPERATION WITH COLD ENGINE
(a) The engine coolant temperature should be below 45°C
(113°F).
(b) Disconnect the EVAP hose from the union pipe.
(c) Start the engine.
(d) Gradually increase the engine speed from idle to 3,000
rpm and check that air suction is not felt at the union pipe.
5. INSPECT OPERATION OF VCV WITH HOT ENGINE
(a) Warm up the engine.
(b) With the engine idling, check that air suction is not felt at
union pipe.

5. INSPECT OPERATION OF VCV WITH HOT ENGINE
(a) Warm up the engine.
(b) With the engine idling, check that air suction is not felt at
union pipe.
(c) Gradually increase the engine speed to 3,000 rpm and
check that there is air suction at the union pipe.

Did these steps and it passed.


Also I checked the PCV valve (which I replaced not to long ago with OEM). I attached a picture, should this be cause for concern? I have the supercharger and it is routed in the stock configuration. I read this thread a couple weeks ago

https://forum.ih8mud.com/threads/pcv-system-with-the-trd-supercharger.916893/

Could I have screwed something up pushing it too hard with the stock PCV configuration? It has been run like this for the last 30,000 miles

 

[ppc]

Have you checked the condition of your engine oil? The PVC valve looks contaminated by moisture.

 

[Proven]

The first item on my hit list for hesitation is the PCV. It is cheap, easy and right on top of the engine. That one in your picture looks like it has a disease...check your oil.

 

[96LX]

Just checked the dipstick quick. It looks good to me, but I can’t say I know what I’m talking about. I did just check the coolant overflow tank... completely empty. I made sure it was full before the trip (it was empty). I did just do a complete coolant flush two weeks ago, so maybe I didn’t get the system completely full and it’s equalizing? Is this wishful thinking?

 

[96LX]

I have checked the oil and the coolant and there are no signs of cross contamination. I did find that one of the new OEM coolant hoses that I installed before the trip did not have the hose clamp attached at the end of the hose but rather in the middle of the hose, and the hose is hanging low on where it attaches to the engine. So it seems I forgot to secure that hose clamp and that is a possibility where the overflow coolant has leaked out. Whew that would've been nasty if that hose fell off during the trip.

My last fuel stop was at a less traveled gas station, to rule out the possibility of bad gas, I poured Iso Heet fuel treatment in the tank, but the problem still persists. The hesitation/ lurching only seems to be getting worse the more I drive it to test. Any ideas on what I should try next ?

 

[Proven]

Could still be bad gas. Fuel treatment doesn’t make gas good.

 

[96LX]

Could still be bad gas. Fuel treatment doesn’t make gas good.

True, however I am now leaning away from that theory because it doesn't seem to be hesitating at all during idle. However I have noticed that the idle jumps up and down about 50 rpm's constantly if that helps

 

[lumbee1]

Does the Cruiser stutter at idle? If so, I would replace the TPS, throttle position sensor. I've had two go bad: the OEM after 20 years and a Chinese knockoff after 16 months. Both exhibited strange acceleration and bouncing RPM's during idle. I replaced the Chinese TPS with OEM and hope to get another 20 years out of it.

 

[Proven]

Your issue is hesitation while accelerating or while cruising at speed?

If you got water in the tank from that gas station it can manifest in strange ways.

Mine bobbles around at idle and has a stumble. Which for what I know is mostly normal.

No check engine light would point me to systems without a sensor. Grounds, bad gas, excessive crank case pressure, or a vacuum hose.

 

[gummycarbs]

True, however I am now leaning away from that theory because it doesn't seem to be hesitating at all during idle.

I don't think that means much with regards to bad gas.

 

[96LX]

Does the Cruiser stutter at idle? If so, I would replace the TPS, throttle position sensor.

There is no stutter at idle, it just seems high at 800 rpm and a bit of a vibration, but it has vibrated a bit while in drive at idle since I have owned it. I hope to test the TPS per the FSM tonight.

Your issue is hesitation while accelerating or while cruising at speed?

Correct

If you got water in the tank from that gas station it can manifest in strange ways.

I don't think that means much with regards to bad gas.

So it can idle just fine with gas that is making it stutter at any rpm higher than idle? Also I don't know if I have mentioned this yet but I haven't noticed any stutter or hesitation at anything over 3000 rpms

 

[lumbee1]

There is no stutter at idle, it just seems high at 800 rpm and a bit of a vibration, but it has vibrated a bit while in drive at idle since I have owned it. I hope to test the TPS per the FSM tonight.


Correct




So it can idle just fine with gas that is making it stutter at any rpm higher than idle? Also I don't know if I have mentioned this yet but I haven't noticed any stutter or hesitation at anything over 3000 rpms

High idle and stutter below 3K is what I was experiencing. My first TPS failure went from bad to worse quickly. Idle was at 800, then 1000, then 1200 over two days. The stutter was during acceleration but constant speed seemed fine. When the TPS finally failed, idle was 2100 and it was difficult to stop the truck.

 

[gummycarbs]

idle just fine with gas that is making it stutter at any rpm higher than idle? Also I don't know if I have mentioned this yet but I haven't noticed any stutter or hesitation at anything over 3000 rpms

Either replace the gas or leave it unknown, but don't assume it's fine because you don't see any thought experiment reason to the contrary.

 

[96LX]

High idle and stutter below 3K is what I was experiencing. My first TPS failure went from bad to worse quickly. Idle was at 800, then 1000, then 1200 over two days. The stutter was during acceleration but constant speed seemed fine. When the TPS finally failed, idle was 2100 and it was difficult to stop the truck.

Interesting, I'm excited to to test the TPS tonight!

Either replace the gas or leave it unknown, but don't assume it's fine because you don't see any thought experiment reason to the contrary.

You're right, I was wrong to assume earlier that it is not bad gas, I just wish the tank wasn't near full. I will try to get the free diagnostics out of the way before emptying it.

 

[Proven]

Is this full tank of gas the same one from the “questionable” location?

Problems started after fill up?

 

[96LX]

No, I put in 11 gallons of fuel from the questionable location, then 15 more gallons to fill up when I arrived back home. I felt the first hesitation going up an incline at about 65 mph about 20 miles from the unknown station, made it the rest of the way home, and filled up (at the station I always do) without another significant hesitation until the next morning, that is when they became frequent.