Dies When Hot

[MannRG]

Thank you @2001LC!! The amount of time, detail, and dedication you have put into figuring out this problem is absolutely remarkable.

I'd like your thoughts on one more aspect of this stumble and stalling issue in the hot afternoon summer sun, when idling at a stoplight. I've had the stumble & stall happen more than two dozen times in the past 6 years that I've owned my 2006 LX, and on two of those occasions (and only two), it sounded like fuel was boiling in the gas tank. The last time was in July 2022 and I actually got video looking down into the fuel filler neck, where you can see fuel shooting across. It was pretty wild. I haven't heard any fuel gurgling or boiling since then but the stumble & stall issue is still very present every summer. I've also seen my fuel economy drop in the past 1.5 - 2 years from around 14 - 15 mpg down to 12 - 13 mpg. I did put on an Ironman 4X4 front bumper in Feb (2025) but the fuel economy had been dropping for more than a year prior to that. Vehicle exhaust is very strong.

Are the fuel boiling (3 years ago) and current low fuel economy, signs of a bad charcoal canister? Does the fact the fuel was boiling at one point change the diagnosis of a failing fuel pump, or is boiling fuel another byproduct of a failing fuel pump?

Thanks again!

 

[2001LC]

Thank you @2001LC!! The amount of time, detail, and dedication you have put into figuring out this problem is absolutely remarkable.

I'd like your thoughts on one more aspect of this stumble and stalling issue in the hot afternoon summer sun, when idling at a stoplight. I've had the stumble & stall happen more than two dozen times in the past 6 years that I've owned my 2006 LX, and on two of those occasions (and only two), it sounded like fuel was boiling in the gas tank. The last time was in July 2022 and I actually got video looking down into the fuel filler neck, where you can see fuel shooting across. It was pretty wild. I haven't heard any fuel gurgling or boiling since then but the stumble & stall issue is still very present every summer. I've also seen my fuel economy drop in the past 1.5 - 2 years from around 14 - 15 mpg down to 12 - 13 mpg. I did put on an Ironman 4X4 front bumper in Feb (2025) but the fuel economy had been dropping for more than a year prior to that. Vehicle exhaust is very strong.

Are the fuel boiling (3 years ago) and current low fuel economy, signs of a bad charcoal canister? Does the fact the fuel was boiling at one point change the diagnosis of a failing fuel pump, or is boiling fuel another byproduct of a failing fuel pump?

Thanks again!

I feel you're missing what I've laid out in above postings. Post you phone number in a PM/DM to me. We'll talk.

 

[usinglinux]

Thank you to all who have posted here.

I posted a thread last year about these same symptoms but chalked it up to a dirty MAF/Throttle Body since the issues did not reappear after cleaning both.

However, this past week I was in Moab and the issue returned. Took the exit off I-70 and wasn't able to get back up to speed because of a loss of power. Engine started stuttering and eventually killed itself. Cleaned MAF and throttle body again, but the issue would persist through the week. Eventually figured out it seems to only happen at high OAT, since I was able to wheel without issue until 2-3pm when the heat peaked and symptoms returned. Which led me to this thread that also led me to investigate and find symptoms of gas boiling, strong smell of old/stale gas when standing near rear of vehicle, and large amounts of vapor leaving my gas cap.

It seems that I fit all the criteria of Charcoal Canister failure. Since this thread is over a year old, could anyone who posted earlier chime in and provide a definitive answer on whether a replacement CC fixed this issue for them?

 

[NM Cruiser]

I had the same issues with my 06LC. The fix was replacing the CC. Expensive but solved the problem.

 

[OEMGUY0720]

Thank you to all who have posted here.

I posted a thread last year about these same symptoms but chalked it up to a dirty MAF/Throttle Body since the issues did not reappear after cleaning both.

However, this past week I was in Moab and the issue returned. Took the exit off I-70 and wasn't able to get back up to speed because of a loss of power. Engine started stuttering and eventually killed itself. Cleaned MAF and throttle body again, but the issue would persist through the week. Eventually figured out it seems to only happen at high OAT, since I was able to wheel without issue until 2-3pm when the heat peaked and symptoms returned. Which led me to this thread that also led me to investigate and find symptoms of gas boiling, strong smell of old/stale gas when standing near rear of vehicle, and large amounts of vapor leaving my gas cap.

It seems that I fit all the criteria of Charcoal Canister failure. Since this thread is over a year old, could anyone who posted earlier chime in and provide a definitive answer on whether a replacement CC fixed this issue for them?

How is your gas cap clicking sound? Crisp clicks when you tighten your gas cap is a good indicator it vents effectively.

 

[Mike NXP]

Thank you to all who have posted here.

I posted a thread last year about these same symptoms but chalked it up to a dirty MAF/Throttle Body since the issues did not reappear after cleaning both.

However, this past week I was in Moab and the issue returned. Took the exit off I-70 and wasn't able to get back up to speed because of a loss of power. Engine started stuttering and eventually killed itself. Cleaned MAF and throttle body again, but the issue would persist through the week. Eventually figured out it seems to only happen at high OAT, since I was able to wheel without issue until 2-3pm when the heat peaked and symptoms returned. Which led me to this thread that also led me to investigate and find symptoms of gas boiling, strong smell of old/stale gas when standing near rear of vehicle, and large amounts of vapor leaving my gas cap.

It seems that I fit all the criteria of Charcoal Canister failure. Since this thread is over a year old, could anyone who posted earlier chime in and provide a definitive answer on whether a replacement CC fixed this issue for them?

Could someone with these symptoms just remove the evap lines and eliminate charcoal canister from the equation to figure out if its causing the problem?? I really don't know, just trying to think of ways to troubleshoot / narrow it down..Probably would throw check engine light but maybe worth a try.

When you open gas cap can you hear fuel bubbling when it happens? Hopefully you don't have to find out anytime soon

 

[usinglinux]

How is your gas cap clicking sound? Crisp clicks when you tighten your gas cap is a good indicator it vents effectively.

Brand new gas cap was installed a few weeks before my trip down to Moab.

Could someone with these symptoms just remove the evap lines and eliminate charcoal canister from the equation to figure out if its causing the problem?? I really don't know, just trying to think of ways to troubleshoot / narrow it down..Probably would throw check engine light but maybe worth a try.

When you open gas cap can you hear fuel bubbling when it happens? Hopefully you don't have to find out anytime soon

Yep, mid-day and low to mid 90s OAT car started stuttering on the way back from chicken corners. Pulled over, took gas cap off and heard bubbling in the tank and saw loads of gas vapor exiting the spout.

I had the same issues with my 06LC. The fix was replacing the CC. Expensive but solved the problem.

Thank you! This is what I wanted to hear before I drop all this dough on new parts, and in the meantime I have found some older threads that mention the same thing. Going to replace fuel pump while I'm at it along with all the other miscellaneous parts 2001LC has mentioned.

 

[OEMGUY0720]

Last resort to fix heat soak 2UZFE stalling in a 100 series is the charcoal canister.
Have you insulated your gas tank and all hard fuel lines undercarriage?
The exhaust pipe sits just a few inches away from the gas tank + radiant asphalt temperature this season are two undeniable ingredients for a very hot gas inside the tank and increased tank pressure (which the average used charcoal canister with 100k miles and above is not able to vent effectively due to the normal wear factor)
The 2UZ is not the only one that suffers from this, the 3UR in the 200 series as well. Upon insulating the tank most stalls have been resolved. If it doesn’t then that’s the time to consider replacing the charcoal canister.