I have a 2008 c6 base model Z51, 3LT WITH 132000 miles
I keep getting a P300 code
I have changed plugs and wires not ignition coils yet, but I don’t know witch one to change. I could change them all,but why
anybody having this problem?

 

Do you have a scan tool that can tell you what cylinder or cylinders may be misfiring...code readers are useless if that's what you have...throw it away !!...at least if you have a good scan tool you can determine what cylinder or cylinders are misfiring...you can try doing a "cylinder drop test"...I think it's easier to remove each coil pack connector while the engine is running and listen for an RPM drop...if RPM drops that cylinder is contributing...if NO RPM change that's the bad cylinder...I just find V8's difficult to do this test...a 4 banger is much easier to hear an RPM change...coil packs are pretty much bulletproof...a cylinder misfire is about the most common problem there is...thousands of Corvettes have this issue so you aren't the only one...I find diagnosing these misfires for the DIY'er is difficult without wasting a LOT of money...find a diagnostic shop in your area...NOT a dealership or a general repair shop...they don't have the advanced equipment to diagnose this especially if it's something mechanical like a valvetrain issue...I use a pressure transducer into the cylinder and can tell what the mechanical issue is without having to disassemble the engine at all and takes maybe 10-15 minutes...pretty "trick" !!...this could also be a clogged injector or wiring for the coil packs or the injectors...too many variables....I'll move this to Tech.

 

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