Talked with Tim at Genesis today. Probably should have called him sooner, but given I picked up the engine a year and a half ago and it has 2500 miles I was not real optomistic. He proved most helpful and is going to explore options to get to the bottom of the problem with me.
He, too, has suggested starting with a boroscope to determine the status of the intake manifold and then work from there. Good idea!
I will check the residue on the plug and see if we can get a better idea if it is carbon or
oil residue. If it were a fuel problem, we still would have to account for the
oil consumption, which I would be at a loss to explain.
Chuck