Zak, it's gotta be the spark plug gallery gaskets. There are 4 of them. The outter seal might be fine, but the 4 ones that seal in the ring around the spark plug galleries are not. Either a gasket problem, or a bolt torquing problem or something. You can buy the whol set of gaskets, which is 4 spark plug gallery ones, the outter ring, and a little semi-circular plug and install them all, or a place like lordco might even sell them seperatly. Anyways, if you need to replace one, you might as well well spend the $50 at lordco and buy the set of gaskets for the valve cover. And thus, your problem will be fixed, unless you have something wierd like a crack in the cover, which is unlikely.