I have a 2002 Silverado Z71 with 5.3 and 4L60E. I have a problem with BRUTAL Detonation(sounds like machine gun fire) at wide open throttle,once it gets above approx 4,000 RPM. It is reduced when engine is cold or when using super unleaded fuel,but still bad. I have no "check engine" light coming on, but at one time I was getting a "lean misfire" code,but that hasn't appeared in months. I had the dealer check it 3 times, twice they used the "on vehicle" fuel injection cleaning system and even replaced they entire catalytic converter system. Each time they cleaned the injectors it was better for about 1 week, then it came back. I have replaced the fuel filter myself twice and each time it appears to NOT be loaded with crap(not at all heavy). Any suggestions?