Spark plug has lot of oil on it

[FloydCrump]

I have a 94 Infiniti q45. I was changing my spark plugs and found out one plug had a lot of oil on it and another one looked brand new. What could be the problem and what would you recommend ?

[Q451990]

to NICO!

Assuming we're talking about oil on the top side of the plug and bottom of the boot coming down from the coil, that means your rocker cover (valve cover) gasket needs to be replaced. The gaskets include the seals that seal the wells that go down into the heads for your spark plugs.

Heath

[FloydCrump]

What about the plug thats not firing? Could it be a bad coil?

[Q451990]

Coil failures are very rare on that generation of the Q45... far more likely a failed injector. That said, a plug under those conditions usually doesn't look brand new. Did you have a dead miss at idle?

Heath

[Infinitiguy19]

I have heard that oil found on the spark plugs can go between the coil and the spark plug and prevent it from firing properly. I know that two spark plug tubes (Cylinder 1-2) were full oil and I think 3-4 were a little wet. But when the valve covers were resealed no difference was noticed.

[FloydCrump]

Yes it does miss and sometimes when u stop at stop sign and get ready to take off it stalls. Someone told me that it could be a bad fuel filter but I replaced it and it still stalls. The car has 204,122 miles on it. I replace the starter 5 days prior to the stalling. Could I have done something wrong there to start the car stalling?