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2009 Corvette Random Misfire

Runner1954

New member
Joined
Dec 11, 2016
Messages
3
Location
Duarte, Ca 91010
Corvette
2009 Corvette
I have a stock 2009 corvette, no modifications with 50,000 miles. I do have a GM extended warranty. My car started to idle rough in Aug 2016. I've completed the normal maintenance stuff and replaced plugs, wires, coils, coil wires, engine upper intake flush and fuel tank flush per GM. MAF sensor was also checked out. My initial post in Dec I described a rough idle issue, no codes. Took my car to the dealer with negative results. I contacted GM and was advised with no codes I could not be helped. Jan 2 2017, I took the vehicle to another shop and after checking my car out the shop came up with two codes P0300 and P0357. My car will idle for 10 seconds at a stop light and its fine, then the rough idle starts where the RPM needle jumps. You can feel the engine rock a little/ rough idle. On a normal 30 drive in stop and start traffic 20% of the time the idle is fine and 80% rough with the RPM needle jumping slightly. The car drives fine with power no hesitation. I returned to the dealer and my car has been there a week with still negative results. The tech advised me that the codes are in the history but not current and the idle seems fine. The service manager is trying to come up with a solution but working with GM I'm not confident he will. Any ideas?
 
P0300 is random misfire
P0357 is likely a fault with the coil for Cyl. #7. Could be the coil itself, the plug wire, the coil driver in the PCM or a wiring and connections issue.

I'm on a road trip right now and away from all my service information, so I can't offer concise repair suggestions but you could try replacing the coil and the plug wire for #7. Also check the wiring and connections on the coil pack. Check the wiring/connections to #7 coil.

If the misfire persists after that and you're doing this DIY, you need a Factory Service Manual.

If you need parts, RockAuto.com is a great source.
 
During Packer's game at halftime, I ordered a fresh beer and was thinking...

If you have a scan tester which can at least read and clear "generic" OBD2 codes, swap coil from #7 to #6 on the other side. Clear codes then readiest. Using that scanner, what DTCs are either pending or set. Post them to the list.

Packers won so that's good luck. Maybe this will be easy to fix.
 
Thanks for the update. Nice win, I have not been a Dallas fan since they fired Tom Landry. My car is currently at the dealership and has been there for the past week. The coils, spark plugs, plug wires and coil harness are all new. Maybe the coil driver in the PCM is the problem or a wiring/connection issue. I have an extended warranty and my thought is to have the dealership repair my car. They have been unable or unwilling to figure the cause of this issue. Initially the car had a code of P0300 and within the last month the P0357 has come up. I've contacted GM because the techs at the dealership are not real mechanics. :L I have a trouble slip with GM customer support and I'm awaiting a return call from them and the service manager at the dealership. I appreciate your information and will forward your input tomorrow. The techs at the dealership are baffled or are claiming to be. Would like to see Green Bay and Pitt in the Super Bowl. Thanks again.
 

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