Need help with a 1984 300 TD. Very slow acceleration, picks up when pedal is pressed to the floor. Adjusted the IP, and adjusted the valves. Verified timing chain with the camshaft and crankshaft settings at TDC.

Cleaned out the gas filter as well. Still slow. It will go from 0 to 60 in about 20 seconds with pedal all the way to the floor.

Any ideas from anyone?