[Dieselyoungguns]

I have and 05 f250 which has recently been acting up. It won't start, it just roles over and and sputters and spits out blackish grey smoke. The problem started a week ago and I couldn't get it started. After waiting a few hours I was able to get the truck started and it ran halfway decent except that it sputters between 1800- 2100 rpms. I was able to drive it all week with the sputtering but this weekend it wouldn't start up again.
The fuel pump on the rail is working, the fuel filters are brand new, turbo seems to be working fine. I just don't know where to go from here.

Thanks for any input guys