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2003 Eclipse Misfire

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misfire p0300
1K views 7 replies 4 participants last post by  Darek 
#1 ·
YEAR: 2003
SUBMODEL: RS
TRANSMISSION: Automatic
MILES: +-150.000

PROBLEM: Hello everyone. I've stumbled across a P0300 (Multiple Misfires), but i honestly have no clue where to look. It's the only code showing. There's no Check Engine light on either.

Basically What happens is when i turn on the car, it mostly instantly stops at first try, second try it starts, pruttles and vibrates intensely. Sometimes also some squeeky noises from the exhaust.
When i accelerate above 2000RPM, it sounds (semi)normal, still pruttles but not as bad as idle. The car stutters in gear or reverse, also gone if accelerating.

To this point, since it started, we've replaced the spark plugs, coils, wires and the O2 sensor in the exhaust manifold, with no luck. The cilinders are clean, no oil or anything, no fuel laying around, nothing. Car is also not leaking.

Anyone have any idea on what i could try next? Or help me in any other way? I could post a video of how it looks/sounds of requested.

Thanks in advance!
 
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Discussion starter · #4 ·
We've tried unplugging the MAF, but that did not solve the idle hunting.
For me the Cilinder Misfires are the first priority as it keeps me from driving the car, and i need it for daily usage so yea. Will let you know if the spraying gives me an indication. Thanks for the quick response!
 
Discussion starter · #6 ·
I think we're saying the same thing. You may have a large vacuum leak that causes your AFR to be out of whack and run crummy. That bad AFR can cause your engine to predetonate or not detonate, generating the P0300. Let us know how it goes!
We've tried your suggestion, and found a small vacuum leak, fixed that but the problem wasn't solved. We have no more leaks anywhere. Would you have any other suggestions?
 
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