dvldog

Sorry, this is long
I tried searching but couldn't find anything relevant.

Okay so I recently purchased a 96 cherokee 4.0. It ran pretty well with a slightly rough idle when I bought it (3-4 weeks ago). After about a week the rough idle got worse, not so much in neutral or park but if I rolled up to a red light I put it in neutral out of fear it would die.

Well I decided to pull the throttle body and clean everything up. The iac was new so I pulled it off and thoroughly cleaned the throttle body. After everything was back together I took it for a test drive and it ran better, didn't notice anything with the idle, ran in drive at a full stop. I took it home and was satisfied.

The next morning the whole family piles in and we take off, we get to the bottom of the driveway and it dies. Starts back up and it gets about 60 feet and dies again. I try again giving it a little more on the skinny pedal and it runs but like crap and its hovering at 3k rpm without shifting.

I scanned it and got a cam position sensor code.

I found the wires going to the crankshaft position sensor were belted from laying on the manifold. I changed that and ziptied the wires back. Didn't change anything.

I pulled the cap and the inside of the distributor looked rough. I swapped it out for a new one. This time it won't even start. I got the engine to tdc, reset the dizzy, still won't start. I called a mechanic buddy and he put it at tdc, reset the dizzy and it still wouldn't start.
We changed the plugs, although they were new we had flooded it.

We got it to started but it smoked, when I say smoked I mean like military grade. After a few minutes the smoke subsided, we backed it out of the driveway and when we put it in drive and gave it a little gas and it choked and coughed and died. We did it a few more times and without getting heavy on the pedal just to get it back in the driveway it dies.

Today I thought I'd swap the pcm as last night when hooked to the scanner it wouldn't let it data log. It kept say "no communication with pcm"

I swapped them with zero change.

Any thoughts?

Cliff notes:
Bought jeep-ran
Week later-rough idle
Week later-dies at red lights
Cleaned throttle body-kinda runs but won't shift
Change parts-give it gas and it dies

Gimmy

so a few things could be a factor and one issue could have caused more. get an OEM crank sensor, and OEM IAC. those parts from autozone do not last. also there is an automatic shut off relay in the passenger side engine bay fuse box. see id that has gone bad.

dvldog

I've seen that more and more today is I've read is to use oe parts on Chrysler.
The crank sensor I know is aftermarket, but the iac was new when I got the jeep. I'll get a hold of the previous owner tomorrow and see where he got it.

I didn't know of the shut off relay. I'll look at that tomorrow. Thank you for the prompt reply.

perez1989

Check for vacuum leaks

holycaveman

Water temp sensor, map sensor, tps can all cause rich running conditions.

Crank sensor won't cause this normally.

Cam sensor bad usually shuts off the injectors

(Blanket statement)