Okay understood and thanks, it was a head scratcher until you threw the idle speed and vacuum numbers out. Definitely have a vacuum leak. But at any rate when you get the coolant temperature up to 190-195 degrees, that spark plug should be hot enough. It's just not reaching self cleaning temperature in that aluminum head. Are you checking the upper hose temp with the temp gun? Get your coolant temperature up into and your tune-up set up right and the plugs should burn off. When adding fuel and oxidizer, you usually need a step or two colder on the plugs to prevent detonation. I definitely would not go hotter, that plug is equivalent to an RC12Y champion.
