Originally Posted by michigan2500hd

Sounds good to me but finding someone in the flint,mi. area with HPTuners is going to be hard. I will check around on mifbody.com since its mostly michigan people maybe someone will have it. Thanks for the advise. As far as i understand the secondary air system just injects air into the exhast manifolds to heat up the cats. is this correct and is it really needed for the car to function properly or just improve emisions?