I have a 1994 grand cherokee. It has been really reliable for me since I got it a few years ago. It has been my every day driver. It started giving me problems about a month ago. I will be driving and it will just die on me. Like it will start running real bad for a min then it will die. It also does this if I let it idle for a long time. Sometimes it will start back up but sometimes I have to let it sit for a half hour or so and it'll start back up. I already replaced the coil... I can't think of what else it could be... Maby a censor or relay. Oh also the fuel pump does kick on and I switched the ac relay and the fuel pump relay.
Also does anybody know what relays are right under the glove box. Hopefully something under there has something to do with the radio

 

What's the fuel pressure in psi, any codes? You really sit around waiting for a half hour on this thing?

 

A engine needs 3 things to run fuel air and spark,It kinda sounds like a fuel problem like a clogged fuel filter or weak fuel pump.

 

well when it happens I'm usually on the freeway. No codes that's what is throwing me off. I'm not sure what the psi is how do I check that... I do know that the pump kicks on every time even when it won't start. I'm always by myself so I can't check for spark but sometimes it'll start back up and get me a little farther down the road. I think that I forgot to mention that it'll backfire before it dies too.

 

It happened once a few months ago and I replaced the feul filter and that worked for a couple weeks but now it dies every time. There is an electrical problem with the radio and the fuses or whatever is under the glovebox makes noise when I have the radio on so maby that is connected somehow

 

Crank position sensor.

 

On the highway the Egr ( not sure if the xjs have them ) Exhaust gas re circulation recycles the exhaust gas back into the engine cylinders if there is one that's what i would think is failing if it is mainly on the high way and the exhaust gas is stored in the charcoal box in front of your xj's fuel tank well at least on mine !!

 

No EGR on a 91-01 XJ.

 

Is the fuse box covered with corrosion?

 

I was waiting for someone to say that because that's what I am thinking. Would it do anything to the oil pressure because it has high oil pressure too... Or a bad sending unit

 

No its pretty clean but I can't really see behind it

 

PCM? Thats my answer every time a Jeep stops when driving or idling.