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Engine is Skipping and nothing seems to help...

Sideswipe

NAXJA Forum User
Location
Rhode Island
Hi,
I have a 2000 Jeep Cherokee and the engine is skipping/running rough and the check engine light is on. It has a 4.0 and I put an OBD system on it and it tells me it is misfiring. I have replaced the plugs with OEM plugs, replaced the Coil Pack bar that provides current to the plugs but it still runs rough and the check engine light is on. The oil seems clean when I changed it (no moisture or coffee colored foam on it) so the head seems ok.
Any suggestions? Thanks in advance
 
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My 4.7L WJ was throwing a P0301 code. Misfire on cylinder one. I changed the coil pack, reprogrammed the computer, changed the injecter and most recently the plugs.
Mind you there was a dealer telling me the first things done would solve the problem.
It has been a week now and it is running a little rough but no codes yet though i'm paciently waiting for the code to return.
I don't have the answer but wish you luck.
Stukboy

As far as clearing the code. You can disconnect the battery and it should reset it.
 
My 4.7L WJ was throwing a P0301 code. Misfire on cylinder one. I changed the coil pack, reprogrammed the computer, changed the injecter and most recently the plugs.
Mind you there was a dealer telling me the first things done would solve the problem.
It has been a week now and it is running a little rough but no codes yet though i'm paciently waiting for the code to return.
I don't have the answer but wish you luck.
Stukboy

As far as clearing the code. You can disconnect the battery and it should reset it.
Thanks for the reply...it actually throwing the P0301, and it said it was cylinder 4 misfiring. I did all those things too, except the injectors. I will give that a try.
Thanks again.
 
i work on cars for a living 20 years now. #1 a p0301 is cyl #1 misfire. p0301 cyl#1 p0302 cyl #2 p0303 cyl #3 etc etc. have you checked compression in cyl #1 and cyl #2 and see if they within 10 lbs of each other. #2 you can listen to the injector and see if it is firing. use a long screwdriver. tip to injector and handle in your ear. listen to all of them and see if #1 sounds different than the others. let me know what u find. cheap coil sets are just that. oe coil set and champion plugs. taiwan replacement parts will burn you every time. trust me its my busisness.

a can of carb cleaner or propane works good to check for vacuun leaks on the intake gasket. little squirt on gasket area cyl #1 could also reveal a vacuum leak in your intake gasket. if it is leaking the cyl will start working with the extra fuel in the vacuum leak.
 
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oe coil set and champion plugs
No champion plugs. Stock NGK on 00+
I would reindex your camshaft position sensor.
It would be good, but considering he is having only one cylinder iwth a misfire I don't think it would help.

Identify which cylinder is misfiring. You say cylinder #4, but the P0301 is for cylinder #1. Swap the injector with another cylinder and see if the misfire moves with the injector. Also, use a noid light to verify that the injector is getting power.
 
Hi thanks for all the replies...when I had replaced the plugs with Champion plugs. Does anyone recommend something different? Thanks again everyone for all the suggestions. Also the coil pack cost a little over 150, I didn't think it was a cheap quality one, does that sound like the right price for one?
 
Run a can of BG44K through the fuel.
 
I'm running Champion coppers. It ain't the plugs. It sucks you bought the coil rail. They're definitely not cheap and yes, what you paid is about average. The codes don't always add up the way you'd like when the camshaft position sensor is off. Either way, syncing it is free, which beats the hell out of continuing the cycle of throwing parts at it.

Does it run rough all the time or does it act up as you drive along?
 
The NGK plugs do make a difference in the common heat soak/cold start issued common to the 00-01 XJ. However, seeing as his case is isolated to #1 or #4 cylinder (Heat soak is usually on #3) I don't think the plugs are the culprit.
 
I'm running Champion coppers. It ain't the plugs. It sucks you bought the coil rail. They're definitely not cheap and yes, what you paid is about average. The codes don't always add up the way you'd like when the camshaft position sensor is off. Either way, syncing it is free, which beats the hell out of continuing the cycle of throwing parts at it.

Does it run rough all the time or does it act up as you drive along?
hi, its cylinder number 4. it is running alot better after I replaced the camshaft position sensor and ran through some Seafoam cleaner. You only feel it when it's idling at a light
 
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