I have a Customers 06 5.9 auto truck with 60hp injectors and a 60/68/14 turbo that I tuned a few years ago. He brought it back to me recently complaining of low mileage and too much smoke. After driving it, the truck has a lot more smoke than it did when I had originally tuned it. Started with the obvious mechanical checks of the turbo and intercooler boots. new fuel filter (holds rail pressure also). I flashed it back to stock and it runs great with zero smoke. Form there I started with just a small timing tune to see what it would take to start smoking again. With just a small timing tune it started to smoke again and continues all the way through the rpm band. I then switched O.S to see if there was something corrupt, with no difference. I am at a loss on this one. Any ideas?