1997 grand cherokee 4.0 2wd:
Cuts off at idle. idle undershoot, hard missfire at times. Fuel pressure is
good (50psi). I replaced the iac motor, tps sensor, pick up coil, coil pack, and
cleaned throttle body. Still cuts off and sometimes wont start for awhile. I
have heard the distributor can cause this symptom.

Anyone have an idea whats going on?

PC

 

I forgot to say there are no faults present, so I can rule out crank sensor or cam sensor.

PC

 

What about your map sensor? You've pretty much hit everything else - TPS, CPS and MAP are usually the big three.

 

when my cps went it didn't trip the fault code. had a hell of a time figuring it out until another jeep owner told me that was it, changed and never looked back. When we removed it was scrapped up for some reason on the inside.

 

Ive been told many things, my jeep is doing the same thing. I heard that the O2 sensor has a lot to do with it, so when I changed the post converter sensor my jeep began to run a little better. I still have to change the down stream sensor which is bank one sensor one. well if you find out whats going on with itlet me know.