Im no pro with these trucks, but I just spoke with my mechanic today about injectors. he said that main clue in knowing your injectors are bad/going bad is not starting after the truck is at NOT. If you have been driving for a while, park it, then go to start it and it doesnt start right away...its usually injectors, especially with the white smoke. Like I said, Im relaying info from my mechanic.....I dont have experience in this!!