I'm posting a question for a friend who has a 77 240D automatic with an odd power issue. It has no power at low speeds but does well enough at highway speed. Apparently it isn't getting enough fuel (when he floors it there is no black smoke). He has quite a bit of experience with MB diesels and said earlier models had a butterfly in the intake to regulate airflow. This one apparently is lacking that. He's not sure what to do next - pump timing? valves? Injectors and pump are excellent (starts instantly at sub freezing temps without plugging the block heater in). I thought it might be the transmission vacuum but he said it shifts through all the gears. Any ideas would be appreciated.