djjeep

Ok first post here, looking for some much needed help. For starters, my 2000 grand cherokee 4.0 was overcharging (started to boil the battery) would run up to 17 volts when running. Ended up with a new pcm and new battery. Having issues now. Idles rough at 900 rpm when you put in gear rpm drops to 500 rpm and stays there, when you give it gas the most it goes up to is 1000 rpm. When in park I can rev the engine up and sounds strong. Got codes 0351, 0352, 0353 and 1391. Replaced cam sensor still got codes, replaced coil pack, no longer have codes. No change in performance, cleaned throttle body, changed plugs, cleaned tps. Looked for vacuum leaks, grounds, connections all seem good. Also installed a second pcm as suggested by 3 mechanics. Also seem to be getting alot of wet exhaust from the tail pipe? Cleaned the IAC.

marshalXJ

I had similar problems with my 95, I changed the fuel filter the the crank shaft sensor, runs great now, but I wasnt able to rev it in park tho with my problem, hope it helps

djjeep

it might be crankshaft sensor..was hoping not because it looks like a bear to get out. Just curious why it seems to idle rough in park but ok when I give it gas in park/neutral.

marshalXJ

It's just one ten millimeter bolt but I had to use 3 extensions to hit it and be able to ratchet and it's such a tight fit and has to be put in and pulled out at the perfect angle lol, plan for a couple hours

djjeep

replaced the crank position sensor yesterday, no change. Idles rough and when you put a load on the engine rpm drops to 500(putting in drive or reverse or even having in park and turning air on). Driving me nuts, ran great before voltage ran high and replaced pcm (twice). Running normal voltage now.

djjeep

Jeep is running great finally...third pcm was the charm. After second pcm replacement..checked every wire, connection and ground. Father in law said it had to be the pcm. With doubts I called napa to see if I could return the pcm i got from them. They ordered me another, installed it today. Cherokee started like a champ, runs great. Question is how can 2 replacement pcms be bad??? Kind of ticks me off but just happy to have my Jeep back.