fastway40

Hello everyone,

My name is Chase and I just got my 1998 Jeep Cherokee 4.0L about a month ago and I love it. It runs great drives great and was well taken care of.

But it has a stumble at Part Throttle at Under 2000 RPM that only happens when it is coming from a cold start and within the first couple minutes of driving, and usually only happens once and then it is fine for the rest of the trip.

If I start it and let it idle and let it warm up to operating temp, and then go drive, it wont stumble ever. If I shut it off after driving and it is warm and then start it right back up and go drive, it wont stumble then either. What im getting at is that it only stumbles once for about 5-10 seconds at part throttle only when it is cold. If I greatly increase throttle or go full throttle it goes without hesitation and runs great and then runs as normal after that and runs good at part throttle. It never dies or significantly slows down, it just stumbles / misfires and wont accelerate unless I floor it.

I did have a the P0351 code come up when I first got the Jeep and hadnt done anything to it yet.

But then I replaced the basics:

- Spark Plugs (old ones were definitely old)
- Distributor Cap and Rotor (and the old stuff was pretty corroded)
- Spark Wires
- Oil Change
- then I checked the engine compression and all cylinders were at 150psi
- I checked the coil with an Ohm Meter because of the P0351 code and it checked out good
- I have check many electrical plugs and vacuum lines and anything out of the ordinary and actually did find a ground wire coming from the battery that was suppose to go to the engine block that somebody forgot to hook back up, and then I found some broken smaller ground wires that I properly repaired.

It still does the same thing with no improvements or worse-ness (lol is that a word?)


So I ask you guys for any help or if you have had the same situations.

I have done a lot of searching through old threads and didnt find exactly what I was looking for.

Thanks

captainwoot

hi there, I had a similiar problem with my 98. Read this thread


https://www.cherokeeforum.com/f2/kee...ts-face-40339/


Good Luck!

fastway40

captainwoot,

thank you for taking your time to help.

i will replace the O2 sesors tomorrow with new ones and hope for the best. At 149k miles i doubt they have ever been replaced. Even if they dont fix the problem, i suppose its a good maintnance thing to do when buying a used car.

tjwalker

149k is a good lifecycle for oxygen sensors. I'd agree and get them out of there!

Also...best not to ignore any check engine light or OBD codes. Even if they aren't giving you symptoms at that time.

Problem is that if you don't chase the code and another problem comes along, that can result in extra confusion in figuring out root cause (of either of them)

If that P0351 code comes back when cleared, that is related to your ignition coil circuit.

fastway40

well i did replace the O2's about a week ago now and the problem is gone! where it happened every single trip before. So thank you so much for the help as this was the first thing i tried after a basic tune up.

The P0351 code hasnt come back since I replaced some heavily corroded cap and rotor parts and replaced the old spark plugs.