[scarceller]

Yes, that's signs of minor detonation. But none of the ceramic looks cracked so that's good. I'd put a fresh set of plugs in and just be sure you stay nice and fat on mixture at WOT below 12.8AFR and you'll be OK. I don't think this is the cause of your issues, I just sort of spotted this look on the top of the piston pictures you posted so I asked about the plugs. Those little metal balls can take a very long time to go away. The balls are parts of the piston top that actually vaporized during the detonation event, usually near the very outer edges of the piston furthest from the spark plug hole near the exhaust valve. If you put the inspection cam back in the spark hole look at the part of the piston closest to the ground, at the bottom of the engine side, lower portion of the piston. But again this is not the issue in this thread.