(Volume up) How do I fix the high pitch rasp/vibration/rattle (whoopy cusion sound as i like to call it.) only heard at 3k rpm or higher, it should sound more fluid like it does at lower rpms. I have Megan racing High flow cats, Isr Y-pipe and an invidia

(Volume up) How do I fix the high pitch rasp/vibration/rattle (whoopy cusion sound as i like to call it.) only heard at 3k rpm or higher, it should sound more fluid like it does at lower rpms. I have Megan racing High flow cats, Isr Y-pipe and an invidia