1995 Jeep Grand Cherokee 4.0L 6-cylinder. It needs some work but runs. What I mean by "it runs" it will die on you as your driving down the road. I got the jeep from my parents as a car I could work on for experience and drive once I got it going. It has been doing this since I got it. I'll get about 20 miles out of it give or take a few miles from start or if you drive a few miles then shut it off then get back in it 10 minutes later then get back on the road and it will die a few miles later. It will start randomly stalling and the rpms will go to zero then jump back up then back down until it finally dies which shuts off the power steering and you have to coast to the side of the road. Then you have to wait about 30min to an hour to get it to start back up and continue driving or sometimes it will just start back up and keep driving. If it is cold outside like winter it runs fine but if its warm like the summer it does this. It seems like either something is overheating or a bad sensor or a random wire is shorting out somewhere. Here is a list of all the things I have replaced: Radiator, O2 Sensor, Alternator, Starter, PCM(Power train Control Module/Motherboard), Battery, Spark Plugs, Heater core Hose and every other hose that needed replacing, Thermostat, and Distributor Coil, this all added up to around $1000 in parts. Here is a list of things I have yet to fix:The Harmonic Balancer is making a chirping noise, the A/C is getting weak so it may need a recharge soon, There is electrical problems with the back windows sometimes you can roll them down sometimes you can't. I've looked all over the internet to try and fix this problem and none of the things I found worked . I checked the diagnostic codes and it is throwing 3 codes 12,11,62.
11=11*No crank reference signal detected during engine cranking.
12=Direct battery input to PCM was disconnected within the last 50 key-on cycles.
62=Unsuccessful attempt to update SRI (service reminder indicator) miles in the PCM EEPROM.
Can anybody figure this one out cause I sure can't

 

Well there you go! "No crank reference signal detected during engine cranking" Crankshaft position sensor. $45 and it's fixed. Use only Mopar IMO!

 

Like Dave said, definitely the CPS. Make sure you have a bunch of extenders handy before starting the job.

 

My mechanic showed me the easiest way. Remove the crossmember and drop the trans down a little.

 

Thanks Dave, I kind of new it was the cps but I didn't want it to be the cps cause those things are a pain in the a$$. I just got the part in the mail and now I gotta get a day off work to install it. Hopefully it goes well.

 

CLUE! The connector is on the passenger's side and the CPS is on the driver's side. When I did mine, I tied a string on the old connector and pulled it across with the sensor, then fished it back after tying it to the new one. It's a real picnic getting the bolt restarted unless you drop the crossmember. Here's another access point, but I've never used it.