2008 c6 corvette
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3rd Gear
Joined: Apr 2025
Posts: 3
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2008 c6 corvette
Hello everyone I’m new to forums, I came here to look for help I’ve looked on here for a while and still haven’t really figured out what was wrong with my car, currently experiencing a random misfire I’ve change plugs, wires, coils, cleaned grounds, cleaned battery terminals and I’m still currently misfiring anything will help 2008 corvette c6 6.2
CF Community Team
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From: Pittsburgh
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Welcome to the forum! You have come to the right place to ask all questions Corvette related...check the easy things first...verify that all plug wires are firmly attached & all of the new coils are actually working
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,621
Likes: 4,066
From: Cape Coral, Florida
Hello everyone I’m new to forums, I came here to look for help I’ve looked on here for a while and still haven’t really figured out what was wrong with my car, currently experiencing a random misfire I’ve change plugs, wires, coils, cleaned grounds, cleaned battery terminals and I’m still currently misfiring anything will help 2008 corvette c6 6.2
Welcome !!…as I’ve said it a few times these last few weeks to our members with misfires other than changing plugs and wires the DIY’er will not be very successful diagnosing misfires as it requires advanced diagnostic equipment like a good scan tool to possibly tell you which cylinder or cylinders are misfiring and a labscope which can narrow it down to just one part…I know this is something you don’t want to hear but you can waste a lot of time and money shotgunning parts at this…unless you know what specific ground may be associated with the misfire you are just wasting time…where are you located as I may know of a diagnostic shop that has this equipment…it may be an electrical issue so if you don’t have some experience with that not a good time to learn…here is a list of the causes…
Plug
Wire
Coil Pack
Coil Pack wiring
Fuel Injector
Fuel Injector wiring
Fuel Injector wiring- bad ECM/PCM
Valve Spring broken
Burned Valve
Cam Lobe worn
Low Compression- Rings
O2 sensor- bank specific
Last edited by C5 Diag; Apr 12, 2025 at 09:52 AM.
Thread Starter
3rd Gear
Joined: Apr 2025
Posts: 3
Likes: 0
Welcome !!…as I’ve said it a few times these last few weeks to our members with misfires other than changing plugs and wires the DIY’er will not be very successful diagnosing misfires as it requires advanced diagnostic equipment like a good scan tool to possibly tell you which cylinder or cylinders are misfiring and a labscope which can narrow it down to just one part…I know this is something you don’t want to hear but you can waste a lot of time and money shotgunning parts at this…unless you know what specific ground may be associated with the misfire you are just wasting time…where are you located as I may know of a diagnostic shop that has this equipment…it may be an electrical issue so if you don’t have some experience with that not a good time to learn…here is a list of the causes…
Plug
Wire
Coil Pack
Coil Pack wiring
Fuel Injector
Fuel Injector wiring
Fuel Injector wiring- bad ECM/PCM
Valve Spring broken
Burned Valve
Cam Lobe worn
Low Compression- Rings
O2 sensor- bank specific
https://youtu.be/7_9pZi30jeA?si=GI6ArGirF5ONsXgy
Plug
Wire
Coil Pack
Coil Pack wiring
Fuel Injector
Fuel Injector wiring
Fuel Injector wiring- bad ECM/PCM
Valve Spring broken
Burned Valve
Cam Lobe worn
Low Compression- Rings
O2 sensor- bank specific
https://youtu.be/7_9pZi30jeA?si=GI6ArGirF5ONsXgy
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,621
Likes: 4,066
From: Cape Coral, Florida
You can diagnose a misfire without a scope but expect to do a lot of guessing especially anything internal to the engine...you can do a compression test but if you hold the gas pedal to the floor and keep it there try starting the engine...it will only crank until you let your foot off the gas...listen for a rhythmic and even cranking of the engine...this can indicate low compression if it sounds uneven...with a lab scope I can do a "relative compression' test without removing any plugs and takes a minute...I'm not familiar with the Icon...if it can do an injector balance test if you have a fuel pressure gauge you can rule that out...does it have misfire monitors where you can tell exactly which cylinder or cylinders are misfiring ???
Thread Starter
3rd Gear
Joined: Apr 2025
Posts: 3
Likes: 0
You can diagnose a misfire without a scope but expect to do a lot of guessing especially anything internal to the engine...you can do a compression test but if you hold the gas pedal to the floor and keep it there try starting the engine...it will only crank until you let your foot off the gas...listen for a rhythmic and even cranking of the engine...this can indicate low compression if it sounds uneven...with a lab scope I can do a "relative compression' test without removing any plugs and takes a minute...I'm not familiar with the Icon...if it can do an injector balance test if you have a fuel pressure gauge you can rule that out...does it have misfire monitors where you can tell exactly which cylinder or cylinders are misfiring ???
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,621
Likes: 4,066
From: Cape Coral, Florida
Having random misfires doesn’t prevent you from doing an injector balance test…I don’t think you understand what the test is….with the fuel pressure gauge hooked up to the fuel rail the scan tool will turn on the fuel pump then fire the injectors for a brief period of time and you see how much the fuel pressure drops…you compare all 8 injectors and if one doesn’t flow as much fuel as the others that is the clogged injector.
