Recently purchased a Diablo Intune 1000 and downloaded the 91 octane tune. I also adjusted the rev limiter and shift points to 500 rpm higher than stock through the first 3 gears. I always run premium 91 octane fuel through a brand name fuel supplier and my 07 Escalade only has 45k miles. Problem im having is at the high end of first and second gear theres a noise coming from the engine. Sounded like detonation to me but when I called Diablo they said the computer would pull timing back long before I ever heard it. They also said these 6.2L engines are known for lifter noise and that's what Im hearing just before each shift. I found it strange that such a refined engine as the 6.2 would not be able to handle an extra 500 rpms. Has anyone else had this problem and does anything that Diablo said make sense?