There are 4 seals that go around the Spark plug holes and fit into the valve cover. However I have this same problem (cyl #2) and I changed my gaskets to no avail. It is really bad now as the hole is damn near half full with oil! Upon closer inspection into the hole I think my head is cracked in that area. I stopped caring though as I am going to get rid of the engine soon :naughty:

 

yea, most likely it's spark plug grommets.

real easy fix, they are accessible after taking the valve cover off.

P/N 12342-PT0-000 at $2.40/each

all dealers should have this part readily available, it's very common to replace, and the same part number is used on most of the vehicles.