Excessive Black Smoke
Several things could be causing black smoke in your diesel pickup:
Problem: Dirty air filter (causing a restriction in the air inlet system)
Problem: Incorrect fuel spray pattern or extra fuel dripping out of the injector (causing the ratio of fuel to air in the combustion chamber to be too high)Treat the fuel system with Diesel Extreme.
Problem: Stiction in the turbo (causing lack of boost pressure)