I've got your 2lb lower pulley. I never had any "possible" detonation with it until lately. I'm not sure if it is detonation, at all; but, it just sounds almost like chattty lifters at high rpm's near shift of the trans . What's your thought. I am chipped with a non-sal chip that was on the truck before the pulley along with an air kit. That's all the mods I have. Like I said, it just recently seemed to get noisey. TIA

 

Sounds like detonation. Get a reburn and let them kow exactly what mods you are running.