2004 Jeep Cherokee Diagnosis codes #3 cylinder not firing

Tiny
GRANDCHEROKEE88
  • MEMBER
  • 2004 JEEP CHEROKEE
Engine Mechanical problem
2004 Jeep Cherokee 6 cyl Four Wheel Drive Automatic

Initial engine light, eventually flashing, and running like very, bad fuel. After two, independent management systerm diagonoses in two states; nobody finds a CAUSE for a # 3 misfire. Mileage is +/- 87,000. The car never actually stalls, and never fails to start; but after driving awhile, it runs VERY ROUGH! Replaced plugs, filters, plug boots, fuel injector and sleeve, and ignition coil. After these changes, auto ran perfectly for over one month.
i am elderly woman who fears being stranded again on I-69 or elsewhere. I see some similar descriptions, for older models, on your site. And they were always referred to service shop for diagnosis. I have done that twice @ almost $1,000.
Please help. Jt
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Thursday, June 10th, 2010 AT 10:17 AM

3 Replies

Tiny
BLACKOP555
  • EXPERT
Did you go with cheap spark plugs and plug wires? Or oem quality.

Same goes for the ignition coil

and only number 3 is coming up? Not a random missfire code just for 3 that is correct?
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Thursday, June 10th, 2010 AT 9:58 PM
Tiny
GRANDCHEROKEE88
  • MEMBER
Don't know what brand plugs/wires were used, but they charged ME $4.19 each. The coil was $195.00--is that cheap?

The last service notes say:
"EEC Tests codes 203 and 303 #3 cylinder misfire. Recheck plugs and coil assy installed previouslyl.
Swapped #2 and #3 plugs; and misfiire stays in #3. Check online NAPAFIX hotline. Several possibilities."
No fix.
Jt
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Friday, June 11th, 2010 AT 7:56 AM
Tiny
BLACKOP555
  • EXPERT
That p0203 code was extremely HELPFUL! That is a code for a a circuit malfunction with the fuel injector on that cylinder. So we know its fuel related now. If you WANT you can take a noid light they are relativly cheap and hook up in #3 connector for injector and crank car. Light should flash. Put in a diff cylinder to compare it. Flashing should be the same. So do you have the pulse? If not its going to be wire related to the injector. And your going to have to check for +12v on one side key on. If thats there and a voltage drop test is performed and the voltage drop is within specs power wire is good and then your going to have to start looking at groudn wire then computer.
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Saturday, June 12th, 2010 AT 6:07 PM

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