I recently did a tune up so today i wanted to check a few of the plugs and see how there burning. All looked super clean. But cylinder 5 had oil on the spark plug threads. The plug electrode looked fine but the bottom rim of the plug had some black. What does that mean??

 

Might be running rich.

 

If it had oil on it its not running rich you either have a crack in your cylinder head or your piston rings are deteriorating. Are you sure its oil?

 

If the oil is on the threads, it is caused by an external oil leak of a valve cover most likely. Oil on the center and side electrode would indicate internal engine issues.

 

I will pull the plug again in a couple days and see what it looks like-will take pic this time. Thanks guys