I have a '92 XJ that recently died on me after parking at a local convenience store. It died twice while I was parked but started up again and drove me long enough to get to the middle of the street and died again. This time it would not stay running for me long enough to put it in drive and turn off the road. I tried for about 30 minutes to get it started. It would crank fine and turn over but it just would not stay running for more than 2 seconds. I could gas it and keep it above 3000 rpm but if I dropped below that I couldn't get it back and it would slowly die on me.

I was parked for about 5 minutes with it running and I do not have an operating temp gauge at the moment so I don't know how hot it was when it happened. I released the pressure in the radiator/lines and it did not seem hot at all, not even a burp. That being said, I don't even think overheating would be the cause of sputtering at ONLY low rpms.

Not knowing the issue, I towed it to the nearest shop to see if they could read a code and they came back with nothing.

The next day I had it towed back to my apartment and it started up and ran for 5 minutes before I shut it down. (fumes in a garage and all)

This Jeep has never died on me ever, there are no codes pertaining to fuel sensors, air sensors, or throttle body position sensors, and it seems to run fine now.

Ive been reading around and there seems to be the following things to do:
fuel pressure check, new TPS, and vacuum checks. I cleaned the IAC yesterday so I am unsure what to do next.

Any help would be greatly appreciated!!

Thanks,

 

How old are the ignition components?with the car running spray the cap and wires with water (out of a spray bottle) and see if the engine starts to stumble, if it does time for a tune up. Other than that you seem to have the right steps in front of you of things to check first

 

The spark plugs were changed when I took ownership of it. This was in 2010. I will give that a shot.

As far as vacuum checks, how does this affect idling? I feel comfortable checking everything but the vacuum system.

 

A vaccuum leak introduces more air into the system than the air measuring sensors are aware of. Because the fuel delivery system uses air measurement to know how much fuel to add in order to achieve the proper air/fuel ratio - this unmeasured air causes problems. Typically the engine will be running lean in this case. Because there is more air than the system knows about, and it isn't adding enough fuel to achieve the appropriate ratio.

This is particularly touchy at idle because the air coming from the vacuum leak as a percentage of the total air in the system is quite high. When the engine is running hard and sucking a lot of air through the intake (and across the sensors - being properly measured) the amount of air coming through the leak can represent a much smaller percentage of the total air. So it is not uncommon for a vacuum leak to cause a lean condition at idle, that becomes less pronounced at higher engine loads.

On a 96+ vehicle, with any OBD2 scan tool that allows viewing live data (I have a $25 model that uses my android phone). This can typically be observed by watching the long term fuel trim (ltft) and short term fuel trim (stft) values. Typically, these values want to be close to zero, indicating that everything is fine and the default air/fuel ratios are being met without much adjustment by the system. When the system detects it is running lean (because of the leak) it will begin increasing the fuel trim levels, and if they get high enough out of whack, eventually the computer will throw a code indicating a lean condition. Unfortunately, a 92 won't make this as easy, and I'm not sure what tools/tricks might be at your disposal. Perhaps someone on here with more knowledge of the pre-OBD2 systems will be able to chime in. (after all, while OBD2 might have been new in 96...troubleshooting air/fuel mix certainly was not!).

By the way, a "vacuum leak" does not necessarily mean the "vacuum system". While the vacuum system uses a vacuum to run vacuum hoses to various actuators to achieve various functions, a "vacuum leak" just means that the engine is "sucking" air in through some source other than what was expected by the system. For example a loose, or improperly installed intake manifold could leave you with a "vacuum leak".

 

fuel pressure is most likely

 

Op has a 92 so no OBD. Unless you have an oscilloscope it'll be haRd to test wave signal
Spark plugs are recommended every 30,000 miles. Basic NGK copper core will be your best bet. And if you have never done wires cap rotor now would be the time to do them.