Did you change the fuel filters lately?
I have an 84 300d and I changed out my injectors and replaced the fuel lines from the fuel filter foward. That might be a solution for your problem. How many miles do you have on those injectors. I had 240000 on mine so I did not mind changing them out as a preventative measure. They are about 60 bucks each and about as hard to change as a spark plug, I did buy a torque wrench to get it to specs. I also replaced all 5 glow plugs. It is an easy job when you have the metal fuel lines off. consider changing that stuff out If all is still original. and try a good 10 count after the glow plugs light goes off. It makes a great difference for me.