I randomly get misfire codes on all cylinders. Maintenance is up to date, new plugs, filters, etc... with 99,ooo miles.

I have never notice a drop in performance nor a misfire during normal operations with or without the CEL on. Im sure i have a coil pack (or two) going bad but how can i diagnose them if they havent completly failed?

thanks

 

search bulletin 09-090 u might need a valve adjustment

 

Did you get the oem spec plug?

Might wanna double check they are all tight.

Valve adjustment should be done proir to 100k. Not that much fun to do, but not a total pita.