I need some help. I got my first duramax the other day. It is a 2004.5 3500. I got if from my brother who has 2 of them and he bought it to use at work for 2 weeks then didn't need it anymore. I have been flipping through other posts and I can't find anything that I thought describes my problem perfectly. I have had 2 mechanics look at it and one I didn't like his answer very much and the other one is a family member and he is stumped. The truck doesn't smoke at all at idle. If I rev it up in park it will puff just a little but not really anything. If I am accelerating in drive it will leave a black haze until I get it to the speed I want. If I am going under 60 I can keep it to the haze if I go over 60 I look like I have a Thick black cloud behind me. I notice the smoke hits around 1700 RPM's right when the turbo starts to spin. I don't hear any leaks but at the same time the turbo doesn't seem to be that load either. I have hooked it up to a computer and No codes other than P0463 fuel lever sensor which my fuel guage does turn off and on going down the highway on bumps, P0670 glow plug module, p0700 transmission control system fault. the turbo showed 14psi which I under stand is 0 and we never drove with it plugged in just gave it some throttle in park and it went to 15.2. all the numbers looked great. according to the mechanics. One mechanic said they wouldn't worry about it and the other one my family member who owns the same exact truck basically says that it isn't right it doesn't have enough power and the turbo doesn't seem loud enough. But see's nothing on the computer saying anything is wrong. I am trying not to question him. I am not a mechanic but I am smart enough to know something isn't right. I don't have the funds to do just start replacing stuff until I fix it. So I need help. My Cummins which was a 12V had more power and didn't smoke near as much as this. I hope that last sentence fires some people up to help me . I plan on doing further testing but I honestly don't know where to look and I am a durmax noob. Break out the red Crayons and draw me some pictures please.