Hey man I think its just your tires throwing your PCM off. I got 05 crewcab 5.3 trust me it will only run 97 with stock tires/ and stock tune. Yeah if I was you I go with CAI, Exaust, Pulleys, Nelson Tune and it will be a different truck. Hey buddy just put a Vararam Cold Air Kit, on his 05 Chevy and I was really Impressed with it. This boy has had both K&N Gen II and Vararam he said Vararam by far pulls harder. Just a suggestion KEEP MODDING