Thanks for the replies, I'll check the rod slop as well. The thing has not even 2 gallons through it yet. Fuel is about 4 months old, about 1 quart left on the gallon that was stored on a shelf in the garage with the excess air squeezed out. The fuel works fine on my other cars so I think it's fine. I'm also going to clean and rebuild the carb then start over on the tune from the factory settings. If that doesn't do it then I may have to resort to violence on this engine and get a new OS
