Hello all, I have a 1998 jeep grand cherokee 6cyl with 239000 miles, I bought it 4 months ago and it would die SOMETIMES at red lights but start right back up, and sometimes start dying when I'm driving, so I downloaded this jeep app on my phone and seen all your threads, I found one that said I should change the crankshaft position sensor, so I paid $100 to a shop and had it replaced, I thought it worked but it only lasted that 1 day

I love jeeps my last one was a 1994 GC same size engine, my new one is a lot cleaner and more comfortable for my family, when I bought it I wanted a jeep that my wife could drive also but with this problem I don't want her driving it at all like that with my kids

PLEASE HELP!!!!!

 

I hate to jump right on the PCM, but it just might be the PCm causing the problem. But you have to look at other things forst and rule them out before buying a PCM. Buy a cheap fuel pressure tester and drive around with the guage where you can see it, when the Jeep starts acting weird look at the fuel pressure and see if it is dropping. It couls also be a bad cam sensor or a relay failing when it gets hot.

 

mine does this before it warms up. my issue is the throttle position sensor.
what happens is when i come to a stop, my RPMs drop too low and it stalls out.

what are you idling at? should be 750. any lower and i would shoot for the TPS.
and assuming this is the issue, do NOT buy a new one from anywhere but the dealership. you wont destroy anything, but it will be a waste of time and money. in my opinion, a dealer only item.

 

I had the same problem with my 98 zj. Turns out the pcm needed resoldering. That fixed my problem with random shutoff and rediculous knocking when trying to die. I am also having an issue with what I believe is the ignition coil plug wiring, which causes it to die once and a while when I first start it. On another note, I put it in neutral when at a stop because the rpms drop which in turn causes voltage drop. People mention tps with that issue but if I'm rolling in drive with my foot off the gas its fine but once I stop that's when the rpms drop.

 

when replacing any sensors on these jeeps, you HAVE to use mopar sensors. especially the crank sensor.

 

I used a napa echlin with zero issues....

 

Same here

 

The point with ANY electronics is they have to be QUALITY, not made in China or Indonesia. I would only trust American, Japanese, or German. Even Sony has stuff made in China now.