My dad has a 2009 silverado with the 5.3l engine but no active fuel management. He purchased the truck new. The interesting part is the window sticker says it does have AFM. I checked the vin on the truck and the sticker and they match. Has anyone heard of this? He bought the truck with his brothers gm discount and the dealer obtained the truck from another dealer out of state. He was surprised it didn't have AFM when it arrived but did not question them about it thinking it was an oversight on his part when he told them what he wanted. He was told by the dealer that the window sticker was removed and lost by the original dealership but I found it folded up in the owners manual just recently.