I am looking at a 03 duramax. Has 130k miles on it and runs and drives fine. It does not smoke from start up or at idle, but when u get on it pretty good it will cover the lane beside you for a good ways. It does have alittle bit of a knocking or tapping noise when cold at idle, but once it warms up it goes away until u give it throttle and then it comes back. It not a quiet knocking noise either. The noise is coming from the engine compartment, and when you take the oil filler cap off you can hear alittle tapping noise coming out of there, but absolutely no blow by. I think it may have some injector problems, but i have been told chevy already replaced them. I just wanted to get some of yals opinions on it. thanks
