well dude i say it's the gasket. i have the same problem on my 92. Actually the oil on the tread is from the oil acumulated in there and when u unplug it the oil will slowly drain down to the cylinder. Did u chech ur tip ? I bet there was no oil on that or the plug wasn't fouled by oil. I sugest u replace the gaskets one more time. the japanese cars have great engines but very bad gaskets. If u plan on getting a new set of gaskest go with one from a dealership not from bubba's discounts autoparts
or some small corner store.