2015 Chevrolet Impala - can’t diagnose after check engine light

impala
chevrolet

#1

Car has 18,000 miles on 3.6 L engine. Number 6 plug oil fouled leading to misfire/check engine light. Dealer replaced plug but no diagnosis. Ideas?


#2

Yeah, #6 has an oil control problem and your misfire WILL come back!

Do a compression test. If #6 comes back low, there has been some ring damage and that is an issue for. If the compression is OK, a valve seal for #6 has likely prematurely failed. either way it is likely Chevy’s problem - check your warranty. At least you got it on record the plug fouled.


#3

Thank you. All that you say makes sense to me and confirms my thoughts.