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1999 Mitsubishi Eclipse Misfire Codes

Tiny
RFRANCO
  • MEMBER
  • 1999 MITSUBISHI ECLIPSE
  • 4 CYL
  • 2WD
  • MANUAL
  • 144,000 MILES
'99 Mitsubishi Eclipse GS Manual transmission, engine rebuilt about 1,000 miles ago. Service Engine Soon keeps turning on with codes:
# P0300 Random/Multiple Cylinder Misfire Detected
# P0301 Cylinder 1 Misfire Detected
# P0302 Cylinder 2 Misfire Detected
# P0303 Cylinder 3 Misfire Detected
# P0304 Cylinder 4 Misfire Detected
Engine idles and runs fine. No feeling of misfiring. The only out of the normal thing is that engine sputters for a second when shutting off, but it's always done it since I got the car. Replaced coil pack, spark plugs, egr valve, air flow sensor. Gone down the list of all possible causes.
Is this a case of a bad ECU?
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Monday, November 1st, 2010 AT 6:03 AM

5 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
I would guess that you have some type of issue with the assembly of the engine, possibly with valve timing or injector wiring.
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Monday, November 1st, 2010 AT 7:15 AM
Tiny
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If it was a valve timing issue or injector wiring, wouldn't it be felt on the performance of the vehicle when driving it? The car runs like new.
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Monday, November 1st, 2010 AT 12:48 PM
Tiny
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Not according to the computer. The computer says it's misfiring
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Monday, November 1st, 2010 AT 1:22 PM
Tiny
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What are the chances the ECU went bad?
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Monday, November 1st, 2010 AT 1:23 PM
Tiny
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  • MECHANIC
  • 20,761 POSTS
It's always a possibility but I wouldn't jump to that conclusion. You really should get it professionally diagnosed.
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Monday, November 1st, 2010 AT 1:26 PM

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