Hmmm, so I just pulled the plugs on my car and I found 3 of the 4 plugs covered in oil...so I'm guessing perhaps a seal or gasket is leaking; or is this normal? What seal or gasket could it be?

 

Is the oil on the threads or the electrode?

If its a little on the threads, thats normal.

If it is on the electrode then it could be a few things.

Check your rings, do a leak down test

 

rubber o ring gasket from your valve cover

 

there is oil around the threads and electrodes...actually there is oil pretty much all over the plugs...even on the other side where the wire plugs in...hmm I'll check out the rubber o-ring.

 

sounds like your o rings are cracker or something...its not good to have oil on your plugs....well i cant thing of anything good that would come of it.

 

Yes, definitely the valve cover gasket, which I believe should have a moulded part that goes around the spark plugs.

When I was tuning Miatas, that was a common problem about every 60k miles. Fortunately, it was an easy fix. Just make sure you don't over-torque the valve cover bolts when you put it back on.