Have a 98 Grand Cherokee 2WD I-6 W/ 210K. While driving, doesn't matter speed, the ZJ just cuts off. all gauges still work, and lights work, but will not fire back up. It cranks, but will not fire. unless I cycle it a few times. I hear the pump priming and every time I have checked, there is fuel in the rail, but will not fire back up. All but one time, the rail seemed to be under pressure. One time I went to tinker with in for a few minutes, put a new cap on it, I cranked it and no start, so I check the rail, and there was fuel, but not much pressure. The fuel pump was changed less than a year ago. No check engine light. Had light initially for high voltage to temp sensor, my temp was not reading, so I replaced that, now it is reading the temp, but this is happening... any ideas? PCM? might try the torx bolt trick. any ideas would be appreciated.

 

I suggest screwing a gauge onto the fuel rail, this may determine if the problem is in the fuel system or not (faulty pump, clogged fuel filter).
Could also be the CPS Crank Position Sensor or the NSS Neutral Safety Switch. I am more of an XJ person but worth looking into.
Good Luck

 

Just getting irritated like a lot of other people. This is my first Jeep, and it is frustrating. When it runs good, it runs GREAT. But then bam! a confusing problem that the check engine light has NOTHING to do with. the first time I dumped $400 worth of sensors in due to believing the check engine light. Has a rebuild head, rebuilt trans, only thing left to do is a computer and a block, and it would be a 10,000 mile used car.... hopefully it is nothing major.. which I don't think it is.. I am going to dig into her on Saturday and figure it out. Have to change my steering box too..

 

A fuel pump less than a year old is still a used pump at this point. Check the pressure before you do anything else. Throwing a bunch of new sensors at it didn't fix the problem and diagnostic codes do not tell you what exactly is wrong. Codes are only a clue as to where you should start looking. What's does " O2 B1 Sensor 1 lean" mean to you? This is a test for you.

 

pressure is good.... 49psi. could it be the distributor. already replaced the cap last week. I can drive about 5 miles, and it runs great, but then it just dies. Again, no sputter, just cuts out. Then, it has to sit for a minute or 2 and it will fire back up. Tried backing the screws out of the pcm, and no change. Someone put phillips screws in, it is not the stars anymore.. it is the screws under the left and right plug, correct? I am thinking distributor, because it was mentioned on the jeep forum that there is a chip inside the distributor that sometimes goes bad.

 

Throw a cam sensor in it and see how it runs.

 

was just reading about that too... ill try that first. though not today... gonna be raining all day. Will let ya know tomorrow..

 

It's super easy to replace, it is right under the distributor cap. Make sure the blade on the dist shaft is securely mounted to the shaft. It it is loose it will throw the cam signal off and cause problems.

 

not the cam sensor. put the new sensor on, driving for about 10 minutes... thinking sweet... it's fixed, and bam... dead.... next... there goes $55..

 

and again, while it was stalled, I checked just to check, and there was plenty of fuel in the rail.

 

I've known the guy at NAPA since we were 5, so I get pretty big discounts on everything... I will try the crankshaft sensor next and cross my fingers... If that isn't it, the only other thing I can possibly think of is the pcm.. other than that, I am lost..

 

Turned out being the Crankshaft Sensor.... problem fixed..

 

That's Good News.
On the XJ it is also the CPS that can give us trouble.