1976 ,300, deisel,---If I increase the rpm to quickly, or from a high rmp ,let all the way off the throttle IT JUST DIES. Im out of idea's on what else to try?? No one in this small town knows anything that helped.

Optional Information:
Pre-1981 Mercedes-Benz 300 d deisel

Already Tried:
It had been sitting for a few years so ,cleaned tank,filters, injector lines. TWICE. adjust linkage,vacum lines good.new fuel,and everything else that the nogood manuel showed!