Hello Scotty! I have a 2010 GMC Yukon Denali Hybrid with 140,000. Code 304 appeared. I replaced the number 4 coil and now Code 300 is present.. Its smokes at startup and makes a noise in engine. It sound like all cylinders are not firing. I put in new plugs and wires.I bought at copart. I have been watching you for years and sincerely wanna thank you for all your time and passion giving us a real avenue of truth and helpful information. Sometimes life saving for the vehicle. I appreciate you Scotty.

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Cylinder Misfire 2010 GMC Yukon Hybrid

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15/06/2024 12:15 pm

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Hello Scotty! I have a 2010 GMC Yukon Denali Hybrid with 140,000. Code 304 appeared. I replaced the number 4 coil and now Code 300 is present.. Its smokes at startup and makes a noise in engine. It sound like all cylinders are not firing. I put in new plugs and wires.I bought at copart.
I have been watching you for years and sincerely wanna thank you for all your time and passion giving us a real avenue of truth and helpful information. Sometimes life saving for the vehicle. I appreciate you Scotty.

Malymal

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Cylinder Misfire code smoke out tail pipe

1 Answer

15/06/2024 1:23 pm

Although a lot of people seem to automatically go for coils and plugs, many other things can cause misfires. See the troubleshooting section of the FAQ.