I am posting this for my boss. He has a 86 300 SDL that has been giving him fits since he had to stomp on it a few months ago while getting on the highway. After getting to work it would not start up and he burned up the starter in the process. A shop used a high end diesel purge as well as replacing all the filters and draining the tank and the lines. It now has intermittent acceleration problems accompanied by billowing black smoke. What happens is when accelerating, it will be very sluggish accompanied with a lot of smoke, then all of a sudden it will take off with the smoke clearing and excellent acceleration. I am not a diesel person so I don't have a clue.
Thanks,
John