Error code P0302

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chappy444

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hello all,
new KJ owner here.
last Tuesday we bought a KJ for my daughters first car from a private seller.
we found a clean 2004 Limited in good condition with 160,000mi. at a reasonable price.
the vehicle looked to be well taken care of (as did the sellers other vehicles and his house and yard)
we test drove the car for about 30 min in mixed conditions and everything seemed to check out.
after we got it home and my daughter drove it around to some friends house she came home and said that the check engine light had come on as she was coming up our street.
I did the key on-off thing and found one error code P0302 misfire on cyl 2.
I replaced all spark plugs (with the recommended NGK units)
and also replaced the coil on cyl 2.
when I took it apart I noticed that the coil that was on cyl 2 was much cleaner than the rest of them and the plug that was in cyl 2 was an autolite and the rest were NGK.
so obviously someone was trying to correct this problem in the recent past.
after replacing all the plugs and the coil I cleared the error with my OBDll reader.
everything was fine for a few hours of starting stopping and driving...
then the CEL came back on. I hooked the scanner back up and found the same error P0302...actually my scanner reported two errors but they were both P0302. but the second P0302 had a (pd) after it...
to be clear, as I scanned the errors the first error said "P0302 misfire cyl 2" and the second error said "P0302(pd) misfire cyl 2" I am not sure what the (pd) means and I couldn't find it in the book that came with my scan tool.

the engine seems to run fine with none of the symptoms of a misfire or the dreaded valve problem I have recently found out about.
the engine idles smooth, no pinging or knocking, no hesitation, no low idle, no trying to stall when stopping, seems to be fine except for the CEL.
soon I will have to have state emissions testing done and it will not pass with the CEL on.

I am guessing my next step is to replace the injector on cyl 2. and do a compression check on that cyl.....god I hope it is not a valve problem we simply don't have the cash reserve for that!!!!

anyone have any insight as to what this can be and how to fix it.
I have read that a bad O2 sensor could cause this but I can't figure how it would be cylinder specific. but I don't know as much about these 3.7L as I would like...
thanks for the advice.
Chappy.
 

chappy444

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anyone have this TSB?

Date Reported:JUNE 01 2004
NHTSA Reference:#10008426
TSB Reference:#1802404


Description: IDLE FLUCTUATION AND OR MALFUNCTION INDICATOR LAMP (MIL) ILLUMINATION DIAGNOSTIC TROUBLE CODES P0300, P0301, P0302, P0303 OR P0304. *TT

Repair Information for NHTSA #10008426
 

Dave

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Similar thing happened to me after a highway trip and I stopped for gas. Gassed up, started it and P0302. It was running fine so I drove the rest of the way home and no problem. Still running fine the next day so I was going to maybe swap the coil-pak with one of the others over the weekend but before I got a chance the code deleted itself. Never figured out what caused it but it went away so I figured it was a fluke and after a couple of running cycles of not seeing a problem, the code went away. Anyway, as long as it is running fine maybe the code will reset after a couple of run cycles. Was the coil-pak an OEM one? I would only use OEM ones personally.

I don't know what the (pd) is after the code? Don't see how an o2 sensor could cause a misfire code on one cylinder. Seems like if there is something wrong with a sensor you would be throwing sensor codes too.

Anyway, someone else will hopefully chime in with more insight.

Dave
 

Leeann

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(pd) means pending...I think. Did you install the new coil with dielectric grease?

I'd throw some Techron in the tank and drive it a bit to see if it clears up. Could be some bad or old gas clogging up the injector. If you can, drive it with the scan tool installed so you can watch the misfire count; if it climbs fast, stop driving it.

Oh, does your scan tool do live data? Guess I should have asked that first.
 

Fredfsb

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Check engine light, code P0302

I had the same problem. In my case it really was the compression off about 70% for that cylinder. Estimate was $2500 to fix it. Since I had 180K miles on it, I was not about to spend that money on it. I also had to pass CA smog inspection. What I did was changed the oil (just before test), purchased some engine additive to clean up the injectors, reset the Check Engine Light with a SCANGAGE. Took it in and it passed the test. Engine runs great, no loss of power or mileage. Check Engine Light came on about 100 miles later but I passed the smog check and don't care. I'm good for two years. Hope to sell it before then.
 

Snail Farmer

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I had the same problem. In my case it really was the compression off about 70% for that cylinder. Estimate was $2500 to fix it. Since I had 180K miles on it, I was not about to spend that money on it. I also had to pass CA smog inspection. What I did was changed the oil (just before test), purchased some engine additive to clean up the injectors, reset the Check Engine Light with a SCANGAGE. Took it in and it passed the test. Engine runs great, no loss of power or mileage. Check Engine Light came on about 100 miles later but I passed the smog check and don't care. I'm good for two years. Hope to sell it before then.

:nutkick::Nonono:
 

04Liberty

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Where are you in MD? I can throw the DRB on it and see if anything more detailed shows up.
 

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