Hey everyone, I just wanted to share some info that many Cherokee owners may benefit from. I purchased the Cherokee that I now have from my brother. When he bought it, it had an intermittent miss that would sometimes cause the engine to die when the engine was at idle (the miss was only evident at idle, raise the rpm’s a little and it would go away). When this happened we had to turn the ignition off before it would re-start. My brother had replaced several sensors and even a PCM to attempt to cure this intermittent miss but wasn’t successful. When I purchased it from him I didn’t worry about the miss, wasn’t a big concern to me. But the miss progressively got worse (it’s been going on for nearly a year now).

Two weeks ago it just all of a sudden started missing continuously and finally set an Engine Light. The code read P0302 (Cyl. #2 miss-fire). These 4.0 engines run pretty rough on only 5 cylinders. I knew it wasn’t the fuel injectors because I could smell the unburned fuel from the exhaust pipe and I could hear a heavy ticking sound coming from the coil pack around cyl. #2. So I replaced the coil pack and the engine ran on all 6 cylinders again. But also after replacing the coil pack, I noticed that the intermittent miss was gone!!!

For the past two weeks I’ve let it idle for long periods of time and not once has it had a miss. This motor runs very smooth now. I know several folks have had this same problem and couldn’t find a cure. In many instances the “Crank Shaft Position Sensor” has been the cure but others, like myself and my brother, have replaced the “CSPS” without satisfactory results.

So for those of you with this same problem, and it appears there are many, don’t rule out the coil pack!

Hope this helps.

Apostle2

 

Excuse me if I'm wrong and I may be but don't all 4.0s have distributers and not individual coil packs?

 

Also the main reason for a 2000- 2001 to miss fire is the spark plug boots,also at times the ev6 connectors do loosen up on the injectors.One more thing on our year xjs is a miss fire when up to temp and you shut it down, then come back with it still hot we will experiance a miss fire on # 3 injector it s from vapor lock ,it will clear itself up upon driving for a couple of miles.Thanks for the info guy.

 

Nope 1999 and older all have distributers ,and 2000-01 have the c.o.p ignition.(coil packs)

 

Thanks for clearing that up for me man. I'm new to working on jeeps. I'm used to working on f150s.

 

Yep, I experienced the #3 injector vapor lock a few times this summer when it was very hot outside. Jeep still running great!