I felt intermittent vibrations while driving, I decided to check my spark plugs. One of the plugs turned out to be flooded with engine oil. I assume that the piston ring must have broke and now lets the oil through. How much would it cost to replace the ring? It seems like it would take a lot of man-hours disassembling the engine to get to the piston.

 

woah there, dont jump the gun.

Run a compression test, also make sure all your injectors/coil(s) are working first.

 

I forgot to mention, I did run the compression tests. Everything checked out.

 

could be your pcv valve letting oil in

 

what about leaky valve seals

 

How about oil leaking from the valve cover past an inadequate (sp?) tight spark plug.
But more likely the Valve stem seals IMHO