I am new to this site so will try to be to the point
I have a 2008 Sierra 1500 4x4 Z21 Crew Cab. I've been thinking of putting a chip in for better performance and fuel mileage. I have been looking at the Diablo Chips and my question is this...

On the 5.3 what will the Diablo chip do to the multi task engine when it is suppose to go from V-8 down to V-4? What can I expect, will it work with the existing program or can I program it in?
Thanks for any help