I have a 1997 Grand Chereokee Limited 2wd. Yea 2wd *rolls eyes* shoulda been my first clue to not buy this pos. Ok so Iv replaced... Crank Shaft, Throttle Position, Mass Airflow Censors... New fuel pump and filter, full tune up, cleaned the throttle body.... It stalls in the rain or in the heat. If its cold though she runs better, idk cuz she doesnt over heat at all, idles REALLY low. Sometimes the fule cuts out other times she stalls completely and has a hard time starting sometimes. Iv taken her to a shop but they are idiots and told me they didnt know what to do. Iv sunk SO much money into her Im done. Now I know my 02 censors are going out but idk if it wont help I rather not fix it.
Any suggestions?

 

Vacuum leak?

 

Sometimes when an engine gets hot it expands enough for a vacuum leak to accure when it otherwise wont...


When its hot and running like this then spray around the the vacuum area with starting fluid.... If the engine revs then u found your leak

 

im 90% sure its a pcm problem, mine did the same then it started stalling every chance it got so after many many hours of research they told me to take the pcm unplug the 3 connections pack them full with diode electric grease and pull zip ties over each plug, and to my surprise it worked ! so i'd give it a try before spending anymore money

 

i know this all sounds dum but my jeeps been running like a champ for about 3 months

 

Already did that

 

Welcome to CF. Read post # 8 in this thread. >https://www.cherokeeforum.com/f5/97-gc-4-0-a-103394/

 

I know you said you already tried the wire ties bit but try shifting the plugs around a bit while tied. Usually its the plug on the right looking at the PCM from front of the vehicle. Its referred to as "Plug A" and carries the pulse for the coil on cavity A7 and if its intermittent you"ll get the backfires, stalls and misfiring. What you need to remember is that the pins make their contact along their length not at the tip by bottoming out the pin. Pushing the plug in tighter isn't the answer so much as keeping it situated so the sides of the male pins are in good contact with the sides of the female pin in the plug end.
With regards to using dielectric grease, the grease is a sealant, not a conductor getting it all gobbed in the pin cavities can do more harm then good. If you want to use a connection enhancer use something like Stabilant 22.
Also removing the plugs more than a few times can start to distort the female pins causing issues. I was fortunate enough to find a new replacement plug at my local dealership, it was 10 years old still new in its package and had been sitting on a shelf all these years. The part number is 5014013AA if you care to try and find one if its needed.

As for the screw trick, its a temp fix at best and how long it will last is anybody's guess. The screws CANNOT short out anything inside. I've had several PCMs apart and all the screws do is hold one of the two boards in the PCM secured to the cover. Loosening the screws just relieves a bit of pressure allowing what is typically a cold/broken solder joint to flex and make contact until it eventually works itself loose again. The most common failure in the 96-98 PCMs is the coil driver. If the screw trick works for you that's a sign that you should replace/repair the PCM cause its got a bad solder joint inside. Another tell tail sign of a failing PCM is if you can tap on it while the enginge is running and make it stall or stumble.

 

I changed my Ignition coil last night, and she started up and sounded great, took her to work, everything was fine. got back in after work to go home and she kept stalling out on me. I dont get it. I really dont. I unplugged the 02 sensors and she seemed to want to not stall, she would go like she was gonna and catch herself. but idk if its because I unplugged them or just because shes a ***** like that lol. This Jeep just keeps me guessing...