I'm sure somewhere on the car there is metal to metal contact....yes the engine was bench tested and runs awsome alittle week in the bottom but great top.....The radio is a FM 26.995 but yes is does it with my AM radio too......It doesn't do it with the engine not running or when at just idel only once I open the throtle....Just doesn't seem right......It didn't do it yesterday but I only ran like 2 tanks as a kind of rebreak-in...