I have just bought a 1982 240D with the 4 speed manual transmission. Its service is unknown & it has 290,000 miles on the clock. It seems the more throttle I give the engine the slower it goes & the less power it has. Back off the throttle a bit and it gains a bit but not very much. Trying to pull a long hill will almost stall the engine completely. The guy I bought it from says it actually did stop on him a few times. It idles fine and a compression check shows good across the board. I’ve changed the fuel filters & carefully adjusted the valves & neither helped a bit. I replaced the fuel injectors & this didn’t help. I suspected an obstruction from the fuel tank to the engine & put a small one gallon tank under the hood & still had no improvement. It is a U.S. model with the EGR valve but the tube between the exhaust manifold has been plugged and most of the EGR vacuum lines are loose. Any ideas? Thanks for any/all replies in advance.