My brotherinlaws 95 3500 has the 6.5 with turbo and about 120000 miles on it. When your riding along it starts to miss and roll black smoke ( wont hardly get out of its own way when it does this )then it will just clear up and run good. It dosnt seam to mater if its hot or cold or how hard your driving it. It starts and stops doing this at randum. I'm thinking the injection pump or the computer controling the pump. What do yall think ?