Stall Issue - No check engine code?

So after some searching I decided to throw in a post, any ideas?

Over the past few weeks I have been having an intermittent engine stall on a 97 XJ, 4.0L. I thought it was water in the fuel, but have been putting that HEET stuff in every fill up. Still have this issue. Only happens at low RPM's, with no check engine light. After stall I can only start it up by putting the pedal to the floor. Even after that it wants to stall, unless I keep the rpm's up.

I checked the TPS sensor with a voltmeter, seems to be fine. When trying to start again, I smell fuel, so I kinda don't think its the fuel pump/filter?

I just did the spark plugs to make sure they weren't the problem.

Distributor issues?

Any ideas guys? Thanks in ahead for any input.

You can smell fuel? Is there a fuel leak? where is the smell coming from? Do you get some not alot of black smoke from the tail pipe when started? Sounds like it might have an issue with a sensor going bad, causing it to run rich. esp if you have to put the pedal to the floor to get it restarted, when you open the throtle plate your increasing the air in the engin and letting it ignite the unburned fuel.
A scan tool will help alot to diag this you need to know what each sensor is doing and what it is reading, so it dosn't turn out a laundary list of parts and no fix.
Ive seen coolant temp sensors go bad before and read -120* so the engin dumps fuel,because it thinks it needs it, and then it stalls the engin.

How dirty is your throttle body and idle air controler?

JEFF: I can smell fuel, and it seems to be coming from the engine compartment. I will have to check on the tail pipe smoke next time it happens.

RickHB19: I will have to also check the throttle body. Are you saying grime/sludge could be clogging up an idle air sensor? I will have to hit it with some cleaner when I get a chance to work on it again.

*****UPDATE****:

It has only stalled after being warmed up (driving 10-15 minutes). After letting it sit for an hour or two, it fires right up, no problems. This leads me to think that it is a sensor causing a rich running issue, as JEFF mentioned. Would a possible air intake temp sensor going bad/short cause this? The reason I ask is that I did the intake swap on it, maybe a yearish ago. And after the swap I had to lengthen (splice) the air intake temp sensor wiring. I thought I did a half decent job on this, but am not a pro yet. Well, when checking the TPS (its good), I wiggled around the AIT sensor wiring, and it threw a check engine "AIT voltage too high" code (I must have shorted it while wiggling).

Sorry for the long story. My question now is would loose wiring in the air intake temp sensor circuit cause stall issues as described above?

Thanks again guys.

I'm thinking bad O2 sensor, which doesn't affect the fuel mix until the engine is up to temp. Try unplugging it and see if the problem goes away. It'll probably through a check engine code, run rough and suck gas without the O2 sensor but if it stays running thats a big clue.

Hmm. Thanks for the idea. I'm assuming you are talking about the upstream O2 sensor? The jeep has 185k on it, so I wouldn't be surprised. I would think it would throw a check engine code if the sensor was off significantly enough to cause a stall.

Thought I would give an update on this issue. It finally threw a check engine code. I was about a day from starting to just blindly throw money at the problem until it went away. Turns out it was an out of spec Engine Coolant Temperature Sensor. After getting warmed up the 'puter would think the engine was still cold and not supply the correct A/F ratio, and finally stall.

Thanks for your help. Hope this helps someone else out!