97 HO stalling/heatsoak issues- PLEASE help

I have a 97 4.0 HO.
for about a year ive been battling what I "think" is a heat soak issue. I say it like that because I haven't really fully came to the conclusion that the problem is heat soak. firstly, the motor is pretty much stock, with the exception of a cheap ebay header and 2.5inch exhaust from the header back.

the problem is this-
after running for a while, at least until the motor gets up to operating temp, the jeep will randomly shut off. the motor will stumble for a second or two then die, but it only happens at low speeds or idle. so, if im cruising at high speeds, the problem never happens. all I have to do is wait for 10-20 minutes and she fires right back up and I can drive away. I feel like im getting excess heat build up under the fuel rail due to the header, but I haven't really been able to prove it.

im already planning on adding a hood vent over the fuel rail, im hoping that solves the problem. if not, I may try wrapping the header or fuel rail with a heat wrap.

right now im looking for some second opions.
I have a wheeling trip coming up in November and I really would like to not have to worry about this.


thanks guys!

no CEL's either

The problem could be fuel or ignition..... Have you checked the condition of the spark plugs to see if any of the cylinders are running lean or rich ?

Several years ago I replaced all of the fuel injectors due to their age and at that time I wrapped the fuel rail with thermal shielding to help reduce the heat absorbed.

Heat soak is a starting issue, not a running issue. I would suspect a faulty CPS. You can have thermal failure where sensors such as the CPS, work and test good cold, but once hot they fail. Upon cooling, they test good again.

Tim_MN said:

Heat soak is a starting issue, not a running issue. I would suspect a faulty CPS. You can have thermal failure where sensors such as the CPS, work and test good cold, but once hot they fail. Upon cooling, they test good again.

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checking the cps is already on my list.

so, if the vehicle is running, even at idle, heat soak shouldn't cause the vehicle to stall?

No. Testing the fuel pressure would be a good idea.

Tim_MN said:

No. Testing the fuel pressure would be a good idea.

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alright.
fuel pump is relatively new, less then a year old. ill check the fuel pressure and let ya know

thanks

bluejeepkid said:

alright.
fuel pump is relatively new, less then a year old. ill check the fuel pressure and let ya know

thanks

Click to expand...

What brand fuel pump? If it's Airtex, less than a year would not be atypical for a failure.

I don't remember the brand, but remember specifically not buying the airtex brand because of their reputation. I believe its a bosch

just thought id close this thread out.
I figured out that a cheap ebay header was putting out a lot of extra heat under the hood, which in turn was overheating the CPS. a new CPS installed and th estalling issue is gone. now I just gotta figure out how to block some of the heat from the header

thanks