I just bought a 1997 Cherokee Country with the standard 4.0L motor. the chassis is a 1997 but the motor is out of a 1998 xj with just over 100k miles on it.



it ran great for the first two days. it then felt like it had a very slight misfire while cruising down the road at about 35mph. I immediately changed the cap, rotor, plugs, and wires in hopes that it just needed a tune up. of course, the problem continued and seemed to get worse. whenever I begin to accelerate it stumbles for a few seconds and then picks up and goes like nothing is wrong. the jeep starts just fine first try every time. after another day of driving it like this it finally through a code. it said the MAP sensor was bad. so I bought a new one and replaced it. the jeep seemed to run better for the first day but soon started doing the same hesitation and misfiring while driving. and now at idle it seemed rough. I then replaced the TPS. this made the problem even worse. it will now idle rough and then die while sitting in the driveway.



my next thought is o2 sensors or possibly crank position sensor?



what could be causing this? I need to solve this quick.

 

just in case anyone has the same issue, I was correct in my assumption. it was the crank position sensor that was bad. I replaced it and it runs perfect once again

 

I'm experiencing similar issues. My code was o2 heating fault and generic transmission codes. I was wondering about the next step if replacing the upstream o2 doesn't work ( it was visually damaged and I'm fairly sure it was my problem.....)
Thanks for the update!

 

CPS, Cam sensor, MAP and O2 sensors and fuel delivery issues are all known causes for the symptoms described, with CPS being a very common one.

Do not regret the tune-up, it's good maintenance if you don't not know when it has been done the last time.