Hello and thank you in advance becuase I don't know much, i scanned my 2000 Volvo s40 and I have a code for misfire in cylinder 4 so I pulled out the coil and there's oil in there? All other wells are dry? I though valve cover but then upon further research I read volvos don't have those? I'm lost now, car doesn't leak any fluids so it's good I think? What should I check? Thanks again!

 

I need to look at my S40 but if its similar to my 850, oil can get on top the cylinder head one of two ways - somebody spilled some oil while filling or there's a tear or loose fit on the PCV tubing up there. Did you check to make sure all the plugs are clean, gapped correctly and properly tightened? Misfires in the S40 can be one of a few things - plugs, sparkplug wires (to the two that have them), coil packs or finally the connectors to the coil packs (needs close inspection as they can crack and allow arcing).