misfire problem
02-12-2009, 09:46 AM
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misfire problem put a cam in the car and it ran fine for about 900 miles then i parked because winter hit and i painted the car and rotors and misc stuff like that moving it around i got real low on gas after it sat about 2 months or so took it out yesterday and it was like it was loading up on fuel if i would just drive it normaly it would misfire and buck real bad but if i would give it like half throttle or more it would misfire and buck for a second or two and the clear up and be fine i think my fuel pressure is a little higher than normal im running about 65psi while judt driving normal?? any ideas
02-21-2009, 05:57 PM
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I put new plugs wires and ran fuel injector cleaner through it it still misfires bad after it warms up but only at crusieing throttle as soon as I go half throttle or more clears up I ran a code reader on it and got the following codes po300,po122,po174,po500 I'm out of ideas give me some thoughts thanks
02-22-2009, 10:58 AM
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i do not have a scanner just a code read so i have no way of checking for knock or look at the tables its so wierd their is no problem at all until about 5 min after it is warmed up and then it is like a switch is flip and all hell breaks loose i have monitors on both o2s (bank 1 and bank 2) and they do not change from when it is misfiring to when it is runnning fine also when it is running fine the backpressure is smooth but when it starts to act up it pops all the time if i engine break with it the car. also when i bought the car it was pretty close to stock but there is an afer market MAf on it ans i belive it is call a MAF translator the little box that goes between the TPS sensor and the wire gioing back to the PCM which while it was running it had a green light and when KOEO it was a red light on it now it is always red dont now if that is effecting something.
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02-22-2009, 11:18 AM
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i do not have a scanner just a code read so i have no way of checking for knock or look at the tables its so wierd their is no problem at all until about 5 min after it is warmed up and then it is like a switch is flip and all hell breaks loose i have monitors on both o2s (bank 1 and bank 2) and they do not change from when it is misfiring to when it is runnning fine also when it is running fine the backpressure is smooth but when it starts to act up it pops all the time if i engine break with it the car. also when i bought the car it was pretty close to stock but there is an afer market MAf on it ans i belive it is call a MAF translator the little box that goes between the TPS sensor and the wire gioing back to the PCM which while it was running it had a green light and when KOEO it was a red light on it now it is always red dont now if that is effecting something.
02-22-2009, 11:45 AM
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i will try that but it misfires at like just barley holding the trottle and if i give it like 1/4 or more it clears up and runs fine it is like when i try to keep it at a steady rpm just driving it will start missind and then clear up when you give it some throttle
02-23-2009, 12:45 PM
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i disconeted the maf and stared it cold didnt help anything but when the car is warm and i unplug it it stalls so that rules out the maf i cleared the codes and drove it around and im only brining up 2 codes po300 (misfire) and po121 which is tps sensor ckt range
03-02-2009, 09:38 AM
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get the icm tested might be good till car warms up. some guy had a problm like that and he put the icm in the freezer for a bit then
hooked it all back up and it worked a little longer the before so he got a new one and it was the fix.
hooked it all back up and it worked a little longer the before so he got a new one and it was the fix.
Last edited by hevymetalg; 03-02-2009 at 09:40 AM. Reason: wrong word
03-04-2009, 11:18 AM
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well it does it when it is cold and warm now it just keeps getting worse it doesnt idle when it is cold and when it gets alitttle warm enough to idle it sounds like im at a gun range from all the back fires it fouled the new plugs i just put in bank 1 is black fouled dry and bank 2 is wet with fuel and my fuel pressure has risen to 64psi at idle which i beleive it should be around 58ish the only thing i can think of effecting it is that i painted the car and maybe some paint worked its way onto the maf or something but at this point i will try anything because i have no clue MAF,MAP,Cam sensor?????
03-16-2009, 04:29 PM
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I just fixed the problem. I change my water temp sensor and it gave me a code, change to a new temp sensor still the code. Still shitty weird random idle. Then i took connector on harness and use a pick and tightend up the female ends inside and used dialectic grease and pluged it in. Cleared codes and drove it 60 miles and no issues with it cutting out or the weird reving at stop lights anymore. No codes but code 650 that means i have no MIL hooked up. 
I hope this may solve somone elses issues.
I hope this may solve somone elses issues. 