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misfire help please!!

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Old Aug 13, 2005 | 03:54 PM
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Default misfire help please!!

i have been searching and i cant figure this problem out. well, i had a bad misfire before i changed my plugs and it went away for about 2 days. then the SES light came on and the misfire resumed. its bad from about idle - 3000 rmp and then its gone. all gears. i have to go and change out the O2's and see what that does. also i am probablly gonna change out the wires. the SES light is the bizarre part. it has been off for about a week and then it came back on today. the misfire has been there the whole time and now its getting worse. what could be my problems. also where is the best place to go and get the codes scanned??
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Old Aug 15, 2005 | 06:05 PM
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no one has any ideas???
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Old Aug 15, 2005 | 07:47 PM
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First thing would be to get the car scanned for for the code, the DTC code should help nail down the problem/tell you what cyl it is. My buddy with SLP long tubes had a similar problem (P0306) - started the car in the dark and the #6 plug wire was arcing on the header - may or may not be the same issue, but happens alot. If you don't know anyone with a scanner Autozone still reads them for free. Get the code(s) read and post them.
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Old Aug 15, 2005 | 08:00 PM
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autozone will scan them for free, as well you can get an obd2 scanner from harbor freight for ~$40.

While you are waiting and shooting in the dark, I'd go ahead and double check all your plug wires at the plug and coil
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Old Aug 16, 2005 | 08:10 AM
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I am having almost the exact same problem. I get code P0300 from my HP Tuners scan. I have recently done headers and re-did the spark plug wires. Checked all of the plug boots yesterday, still a misfire. I am going to try and make sure all of the coil terminals are connected good, then see if I can make sure no wires are touching the body or each other. Relocated coil packs are cool, but a pain in the *** to get right.
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Old Aug 16, 2005 | 10:31 AM
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Same issue here....0300 code now

I replace PCM and cam sensor recently but the 0300 reapeared a week or so later...

So this weekend I replaced alll the plugs, wires, and threw in a new crank shaft sensor too.... I also took off the stock metal spark plug boots as they might be causing an arch,,,

It is not together yet so I cant tell if it is fixed....
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Old Aug 16, 2005 | 12:29 PM
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Damn Robert! I really hope I am not headed down that road .
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Old Aug 16, 2005 | 01:44 PM
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Several weeks ago my car (99 Camaro) died in front of my local GM dealer. They had it for two weeks before they told me it was a bad PCM. The PCM was under warranty so - don;t say you modified anything in the PCM or they will void your PCM warranty.

So then I got the car back and drove it away only to find out the techometer did not work. I returned the car immediately for the dealer to look at and they could not start it. UHG!!!!!

They said they forgot to install a cam sensor so rather then wait another two weeks I bought the part and installed it myself.

It ran but I got a P0300 code recently. The car has a missfire condition after it warms to operating temporature.

So I checked the valve springs, cam retainer plate, and replaced the plugs and crank shaft sensor this weekend. I need to install a few more parts before it is ready to test....

...good luck with your misfire problem....
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Old Aug 16, 2005 | 02:05 PM
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a friend of mine had some misfire issues on his 99 T/A, turned out to be a broken intake valve spring. but of course, the the car ran really bad under that condition too.
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Old Aug 16, 2005 | 02:47 PM
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MIne idles great and will run fine until it warms to full operating temperature. It then runs like **** - like a plug wire is off.....

I checked the valve springs this weekend and they are OK as far as I can tell. I am running double springs so I assume if I broke one spring the other would take over anyway...
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Old Aug 16, 2005 | 03:17 PM
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some of y'all might consider doing a case relearn.
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Old Aug 16, 2005 | 04:03 PM
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robertbartsch --- that sounds like my exact problem....i have to get my new rear installed then im gonna take it to autozone and get it scanned and see what the code is. thanks guys ill keep ya'll updated
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Old Aug 16, 2005 | 04:07 PM
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TA Quickness:
Is a case re-learn posSible with LS1Edit?
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