Jeep stalls when stopping after driving distance at high speed

TheDWord

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Long detailed post ahead. Thanks for reading!

2001 TJ automatic, 4.88 gears (relevant for the speed figures below)

BACKGROUND:
I spent a ton of time late 2021 and half 2022 trying to troubleshoot a misfire issue. Replaced just about every sensor; Mopar replacements where possible, forum recommendations otherwise. Here's a link to my previous thread on that - https://wranglertjforum.com/threads/yet-another-misfire.59466/.

I ended up taking my Jeep to an area diagnostic mechanic who, after keeping at the shop for nearly a month, returned it to me sorted. Based on their description of the problem, it came down to the crankshaft position sensor and camshaft sensor being out of sync. But it sounded like they had struggles getting that corrected. Through the latter part of 2022 and all through winter it had been running great, but I've recently started having some interesting trouble. I don't know if my current issue is related but it's hard to believe it's not.

ISSUE:
The problem seems to be heat related. Not that the Jeep gets particularly hot, temps are normal, but the problem is certainly worse when driving on the freeway compared to taking back roads or putting around town. I can drive around all day on city streets and easy trails no problem, when I start to drive distances is when I start seeing issues.

If I take backroads between home and work, roughly 25 miles at 50mph average, as long as I don't come to a stop there is no apparent problem. Once I come to a stop, it will idle ok briefly then start rumbling (feels like a bad misfire) and die. If pop into neutral and come to the stop out of gear, it will likely behave normally, maybe a slightly rough idle. Typically, if it dies, it will start right back up and drive off like nothing happened... until the next stop. Rinse and repeat.

Slightly different story if I take the freeway (70mph speed limit) for the same home to work drive. Again, until I come to a stop, there are no apparent problems. I could probably put hours of road behind me at speed. This is where things are different; when I come to a stop it will just die, no rumbling, no neutral roll to keep it running, it just dies. Unlike the lower speed drive, unless I get lucky it will not start right back up, it will just crank and crank and crank. Even then, I have to rev the engine and slam into gear to get moving. I've had to wait up to 30 minutes or so before getting the chance to drive off.

Through all of this I've only had a code pop on time during one of the slower drives; P0352 (Ignition coil 2 circuit). I had a spare coil rail on hand so I went ahead and swapped it, but the drama continues.

One thing I'll note but I'm not sure it's related. When get in to start up, its hit or miss whether it's going to crank for a bit before firing or whether it's going to fire right up.

If you're still here, thanks so much! Hopefully you have some insight or can get some help from the thread if you're facing similar issues.
 
Long detailed post ahead. Thanks for reading!

2001 TJ automatic, 4.88 gears (relevant for the speed figures below)

BACKGROUND:
I spent a ton of time late 2021 and half 2022 trying to troubleshoot a misfire issue. Replaced just about every sensor; Mopar replacements where possible, forum recommendations otherwise. Here's a link to my previous thread on that - https://wranglertjforum.com/threads/yet-another-misfire.59466/.

I ended up taking my Jeep to an area diagnostic mechanic who, after keeping at the shop for nearly a month, returned it to me sorted. Based on their description of the problem, it came down to the crankshaft position sensor and camshaft sensor being out of sync. But it sounded like they had struggles getting that corrected. Through the latter part of 2022 and all through winter it had been running great, but I've recently started having some interesting trouble. I don't know if my current issue is related but it's hard to believe it's not.

ISSUE:
The problem seems to be heat related. Not that the Jeep gets particularly hot, temps are normal, but the problem is certainly worse when driving on the freeway compared to taking back roads or putting around town. I can drive around all day on city streets and easy trails no problem, when I start to drive distances is when I start seeing issues.

If I take backroads between home and work, roughly 25 miles at 50mph average, as long as I don't come to a stop there is no apparent problem. Once I come to a stop, it will idle ok briefly then start rumbling (feels like a bad misfire) and die. If pop into neutral and come to the stop out of gear, it will likely behave normally, maybe a slightly rough idle. Typically, if it dies, it will start right back up and drive off like nothing happened... until the next stop. Rinse and repeat.

Slightly different story if I take the freeway (70mph speed limit) for the same home to work drive. Again, until I come to a stop, there are no apparent problems. I could probably put hours of road behind me at speed. This is where things are different; when I come to a stop it will just die, no rumbling, no neutral roll to keep it running, it just dies. Unlike the lower speed drive, unless I get lucky it will not start right back up, it will just crank and crank and crank. Even then, I have to rev the engine and slam into gear to get moving. I've had to wait up to 30 minutes or so before getting the chance to drive off.

Through all of this I've only had a code pop on time during one of the slower drives; P0352 (Ignition coil 2 circuit). I had a spare coil rail on hand so I went ahead and swapped it, but the drama continues.

One thing I'll note but I'm not sure it's related. When get in to start up, its hit or miss whether it's going to crank for a bit before firing or whether it's going to fire right up.

If you're still here, thanks so much! Hopefully you have some insight or can get some help from the thread if you're facing similar issues.

Have you investigated the fuel injectors and rail? Do you have an insulation kit installed on them?

Kinda sounds similar to the common fuel vaporization issue.
 
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Have you investigated the fuel injectors and rail? Do you have an insulation kit installed on them?

Kinda sounds similar to the common fuel vaporization issue.

I have.

The fuel rail isn't new but I have tried 2 separate rails. The injectors were replaced with this kit, https://www.ksuspensionfab.com/store/p71/Remanufactured:_4_Port_Upgrade_Injectors_YJ/LJ/TJ.html#/. While I was at it replacing those, I added heat protection.

Unfortunately, those items made no difference.
 
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Have you investigated the fuel injectors and rail? Do you have an insulation kit installed on them?

Kinda sounds similar to the common fuel vaporization issue.

Also, the check valve is designed to keep pressure on the system - and gas is hard to “boil out” under pressure-

If it’s running it really should be under constant pressure, but the pump could be going out-especially if you occasionally get hard starts.


You might look into all that.
 
You might look into all that.

What is your suggestion for "all that"? The fuel pump has been replace within the 10k miles I've owned it, along with the other components I've mentioned to have been replaced.

Pretty much the only part of the fuel system that hasn't been replace is the feed line. What do you think is the likelihood that a problem in the feed line would cause an issue like this?
 
What is your suggestion for "all that"? The fuel pump has been replace within the 10k miles I've owned it, along with the other components I've mentioned to have been replaced.

Pretty much the only part of the fuel system that hasn't been replace is the feed line. What do you think is the likelihood that a problem in the feed line would cause an issue like this?

First I see the pump mentioned-

The line runs close to the precats- wrap it and the 2 evap lines there with reflective heat tape, and see if you can find this thread-

E2C5B63D-7B27-4835-95F1-717F62327594.png
 
Sounds simple but have you checked for a vacuum leak? I had similar issues with rough idle and almost stealing after it got warm and coming to a stop. Searched for weeks for the issue and it was a simple vacuum leak.