[rcassidy]

By Chance could this be weather related? I get a backfire every once in a while, but only on 85+degree days. i.e when the air is warmer and less dense causing the motor to run slightly more rich. This doesn't happen in cooler weather and the engine tuner said I could afford to jet it down one step during the summer months if I wanted to as it would run slightly rich in the hot weather, but normal in the spring/fall type weather. Just a thought.