Oil on spark plug

[squeak_cg]

Hey guys,

My brother got a 97 mustang a month ago or so and it has a 98 Cobra motor in it w/ 80k on it. He got a check engine light and pulled the plugs. Found that one had some oil on it, causing it to miss. Cleaned it up and it runs okay. Any ideas on what would cause this or what to look for? Thanks for any input.

Adam

 

[40th GT]

You should do a leakdown test and if the leakdown is too high, it's a sign that you're piston rings are worn. The oil could be leaking through the rings and onto the plug.

 

[Red2000GT]

Valve seals are rumoured to be a problem on the older 4-valve engines.

 

[the98stang]

Yea it's most likely the valve cover gaskets. If the rings were shot oil would be all over the spark plug threading. Plus the car would burn oil, spit out blue smoke, and run like sh1t. Check the valve covers.