Random Cylinder missfire's
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Random Cylinder missfire's
I have a 2008 cobalt ss tc and it has injen cai injen charge pipes mpx downpipe mpx catback exhaust. It is throwing a random misfire dtc. noticed the electrodes on my spark plugs are much lighter then they used to be. measured 65 psi before the fuel pressure regulator . did a compression test also. 165 psi across the board. Cleaned MAF sensor, noticed way high air fuel ratio's at higher rpm's but normal at idle, I believe idle should be at 14.75 to 15 but not positive. Any further suggestions to figuring out this problem would be great, thanks
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first scan cylinder 4 misfire second scan multiple cylinder misfire third scan cylinder 1 misfire and there are no non-cel illuminating codes. also just got done putting in a stage 3 ky clutch could I have screwed up the crank position sensor ? also have a superchips programmer currently stock tho
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This is gonna sound absurd, but if you're on the factory battery, replace it. Get a good battery, Duralast Gold, etc. No joke, that stopped by misfiring and I know that's been the solution to a lot of people's misfire problems on here.
#8
My random misfires on all cylinders was caused by spark blugs. They were black is **** so I wirebrushed them, re-installed them, CEL gone, and car ran like a champ. Even got me 30mpg afterwards. Shifts better, idles better, breathes better and saves me money at the pump. Eventually replaced the old ones with new ones after O'reily's had to special order mine.
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My random misfires on all cylinders was caused by spark blugs. They were black is **** so I wirebrushed them, re-installed them, CEL gone, and car ran like a champ. Even got me 30mpg afterwards. Shifts better, idles better, breathes better and saves me money at the pump. Eventually replaced the old ones with new ones after O'reily's had to special order mine.
just replaced them a couple weeks ago gapped them to .035
been doing alot of trouble shooting the past few days and it
looks like its leading me to believe the MAP sensor is bad
its around 33 kpa at 20 vacuum
isnt it supposed to be in the 60's ?
#10
Not sure. I gapped mine originally at .035 too but at a cold start I'd get stumbling and after I'd get on the road it'd be fine. So I tried .032 and that solved everything.
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would a bad map sensor and or tmap sensor cause misfiring
also my map sensor has incoming voltage of 5 but no outgoing voltage. that calls for a new map sensor right? opinions would be great thanks
Last edited by GAGNE; 03-20-2013 at 09:34 PM.
#18
mine was at idle. p0300 everytime i started the car
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