Need Help Troubleshooting Engine Stalling & Sputtering During PM Only

Do you have a "Check Engine" light? You need to read the OBD codes. If this engine has electronic fuel injection, one place to look is the MAF (Mass air flow) sensor or the O2 sensors. The OBD codes should indicate a problem with either of these, and set the "Check engine light"

Sounds like the wiring harness at back of cylinder head is grounding out on stud...or dirty throttle body.....or carbon buildup on valves.....or a weak battery.....or the idle air control valve.....

SolarEagle it appears you zero in on the root cause. Thanks

Thanks Everyone for replying

Bought this car new, I always had a problem with the engine light being on and dealer mechanics always said it was a leaky gas cap and since I live in a state where cars are emission tested every two years, I must have had it diagnostically tested four time and bought a gas caps each time. I would immediately get it emission tested and in a couple days the engine light would would come on again. I do not have any confidence in dealer's mechanics.

On April 5th of this year took it to mechanic that did a smoke test and found that the Evap Cannister was leaking. Had it replaced and the engine light have not come on since then.

Before leaving work today, I open gas cap (could not hear or feel any pressure being released) also shook the car hoping that would help and replace the gas cap. Didn't want the engine light to come on because it running with the gas cap off. It was cloudy all day and only reached 75F. I was able to drive about 20 minutes when on the highway it started sputtering and only stalled when I was pulling into my driveway.

I will be replacing the fuel filter.

Did you check the air filter?

Summer humidity might be playing a role.

Also, mostly out of anger but it sometimes helped, take it out away from traffic and stuff the gas pedal to the floor on a nice straight road.

I miss the old days of figuring out if it was fuel or spark.

Maybe a pressure test on your fuel line?

Gas treatments/dryers are usually alcohol, and won't help since we now have it added to all of our gasoline.

I'm in the fuel injection camp..sensors like water temp

I would look at what the water temp is when it happens.

I had a dodge 318 1988 ramcharger that had been running cold but ran fine. I had the thermostat but was to lazy to put it in. On a real cold day the wife made me change it. After changing it I let it warm up and the temp gage came up to normal that it had not done in a long time. So I thought done and was about to shut it off when it shut down. The strange thing was that in drive the engine ran fine in neutral it would stall. I increased the idle speed and called it a night. The next day the idle was way to fast. It turns out the computer had to learn the new higher temp.

That is one of the things that can drive you nuts you fix something and the computer has to learn to like it so you think it is not fixed.

When the car begins to stall, can you save it by putting the transmission in neutral?

I had one that the torque converter would lock up and stay locked up causing erratic engine at speed and stall when stopping. It was okay when cold but after 20 minutes it would lock up. Had to be in drive. Eventually putting in neutral would not free it up until it all cooled down.

The symptom that it runs okay in the morning needs to be understood to help find the issue. What is different besides time of day? Do you go down hill to work in the morning? Is the trip different on way home? Do you ever go on long trips in the morning? Do you have a passengers one way and not the other? Different roads allowing different speeds? Does the radio have symptoms at the same time? Is the A/C kicking in and the compressor locking up? Check the alternator for locking up too. I had an alternator lock up and drag the car to a complete stop from 70mph ( 4 Cyl).

I will try this, if it starts stalling while at a stop

Is it any better with daylight savings time?

Just kidding. These Jeeps with the inline 6 engine are tough on crankshaft sensors. They are mounted to the transmission bell housing at about the one o'clock position. Just a pain to get to. But, first thing you should do is get a reading from the on board computer. Knowing what the computer sees will help match the problem with the codes. Let us know.

I highly recommend you pull the codes from the OBDII, then reset it. The codes can guide you to where the problem lies.

Logically, here's my thoughts. Since it doesn't sound like it's a problem with a cold vs warm engine, I'd look for things that are affected by the environment. If it acts up when it's warmer outside, that could mean there's a problem with the fuel system. As the outside temperature warms up, more gas will go to vapor.

1. The evap system could be the culprit, especially if you top off the gas when you fill it (liquid can get into the system).

2. More likely is the fuel pump. Warmer fuel means more pressure in the fuel system, which could have an effect on a weak fuel pump. There is also a recall # 34192 for an electric fuel pump problem - check into it.

3. Could be electrical - as things warm up, they expand and could cause a short or open circuit.

4. Could be the computer. Very unlikely, however the environment could have causes a weak solder joint on the board and when things warm up, the circuit goes open or short.

Let us know what you find out and good luck. These are tough to diagnose.

Good Day Everyone

Well this morning it sputter while on the highway about 20 minutes into the drive and when I arrived at work it kept stalling in the parking lot.

I took it to the mechanic around noon, it sputter on the highway about 15 minutes into the drive and then it stalled on the highway and I coasted onto the median strip, waited a couple of minutes and restarted it. It kept sputtering on the way to the mechanic and when I pulled into their driveway it stalled. The mechanic took it for a road test and again it didn't do anything. I am beginning to think this car hates me.

I mentioned to him what everyone been suggesting, he stated that the computer codes would not indicate what the problem is.

Because this problem is intermittent and usually occurs when the engine had warm up, I am thinking that the fuel filter is retarding the flow of the gas and that maybe the engine heat is causing the gas to flash over into vapor and causing a vapor lock. So I asked them to replace the fuel filter which they immediately stated may not fix the problem.

Was able to drive home with no problems, so tomorrow will be the true test. I'll let you know how it goes.

I truly appreciate everyone help

"Was able to drive home with no problems, so tomorrow will be the true test. I'll let you know how it goes."

Thank you! Lots of good answers on here, but right or wrong, it's good to know the results.

Good Day Everyone

Well no problem going to work; however, hell of a time getting home

It stalled out after five minutes, It didn't want to restart for about ten minute, I thought I was going to have to get it towed, because I was in a turn slot blocking people a guy from work and me pushed it to the side so the people could get through.

When it finally started and I was able to put in in gear without stalling, I was able to sputter to a parking lot. Because all the times, I took it to the mechanic, they didn't had the problem I decided to turn off the engine and let it rest. After 15 minutes I tried again and didn't have any more problem getting it home.

I decided to take the car this morning to the Jeep Dealer.

Hope they can reproduce the symptoms, and fix it.

Good luck!

The diurnal nature of the problem probably points to the fuel system. The JGC has a sealed fuel system, as the ambient temperature increases as the day progresses the pressure in the system rises. Normally this should be compensated for by the pressure regulating valve feeding the fuel rails, and the pressure relief valve that returns the excess fuel to the tank as they do their balancing act to keep the pressure to the injectors constant.

If either is sticking then you will get a low pressure to your injectors which results in an overlean condition; no matter what you do to the accelerator you won't be able to force sufficient fuel through the injectors.

Another place to look is a part of the pollution controls that few people are aware of. There's an automatic system that periodically pressurizes the entire fuel system to check the integrity of the hoses, tank, carbon canisters, etc. It usually operates in the background but if one of the solenoid valves or sensors goes off calibration you can go nuts looking for the problem because it looks like an intermittent, though the OBDII system should throw a trouble code to help diagnose the problem.

Personally I would rule out the fuel filter, when they get clogged the problem usually manifests itself as "...the car runs fine below 65 mph, but if I try and accelerate or climb a hill it feels like I'm running out of fuel...", which is true except that the tank is full but the clogged filter is acting like an orifice and reducing the flow when you need it the most.

when I first read your thread I did a check and found many owners had complaints relating to "the wiring harness", they were not including the stalling aspect, I bet your dealer went right to the problem rather than searching for the hidden gremlin.best of luck

Thanks for coming back to tell us what you found!

I am glad it is running well for you. I feel the wiring harness fix was good and suggest you look the repair over so if any symptoms reappear you will recognize if the harness has changed to cause the issue again.

Now for some questions.

The car is 10 years old with only 21000 miles, did you buy it used or was there a different use before you started driving 18 miles a day?

The soot in the air-duct is a really curious symptom and unless the air filter was not installed or replace recently the soot must have come from the engine that means backfiring, I suggest checking that again in 2 weeks to see if the soot is accumulating again. What does the inside of the tailpipe look like?

Lastly, with the era of electronic spark control it is very unusual to have that eroded spark plugs symptom. I again would look at them after 2-3 months to see if that issue is still happening.

I bought this car new, the wife drove it until the beginning of this year, when I bought a new 2014 Jeep Grand Cherokee and got rid of the 1998 Jeep Grand Cherokee. When I started driving this car it had 17,500 so she average 1,750 miles per years, where I am probably averaging about 5,000 a years.

I do not understand why there was soot in the duct between the Air Cleaner and Carb either, because it never was driven without an air filter installed, and everytime I replace it I do not remember it being too dirty. Unless, the air filter's filtration capabilities degrades with age due to moisture or something else.

Thank you for your recommendations. If I find anything unusual, I'll update this thread

Glad it is fixed. Thanks for letting us learn. I have seen harness chafing issues mentioned before, but they were in the area of the back of the valve cover, passenger side. And the usual complaint was rain and engine torque related.

As for the soot, if the engine is at speed, and there is a backfire, the spark from the cylinder will be able to light everything in the intake runners if the intake valve is open. That explosion will leave soot all the way back to the air filter. Remember, you had your foot on the throttle, so it will blow fuel mixture past the throttle body.

Good luck.