[Ramtime7]

Yesterday as i was driving home from work i noticed my check engine light come on. So i stopped at advanced auto parts to read the code. I'm assuming its either the coils or the plugs. The truck has 62k miles on and i'm not sure if they've ever been replaced because i bought the truck used. I also put a cherry bomb muffler on it last week (idk if that would effect it) Any help would be greatly appreciated.

 

[snrusnak]

Upper bank plugs are due for replacement at 48k miles. May want to replace them first. Or swap the #3 coil with another cylinder, clear the code, and see if it comes back on the same cylinder or the one you swapped it with. That should identify if it's a plug or coil for you. Also could be the pcm but doubtful.

 

[Ramtime7]

i swapped #1 and #3 coils and cleared the code so i guess now it's a waiting game

 

[snrusnak]

Cool. If it gives the same misfire code on the same cylinder, it's most likely either the plug, or could be the pcm.