New on here, I bought a 2009 5.3 SLE GMC Sierra.
The previous owner bought it Brand New of the Dealership.Its a 4×2 crew cab. When he gave me the title it showed 12miles. The truck is super clean inside and out. I put a 3" leveling kit, cold intake, msd wires, AC Delco Iridium plugs, exhaust.The truck drives Good until you floor it, Freaking thing moves and it does not cut off at 98. I have had a bunch of trucks, new and old but this 2009 gmc has me thinking. I think I just answered my own question? The truck has somekind of programmer or tune.
Any thoughts would be appreciated.