86 300SDL weird engine hesitation
 

Ok guys here is an issue I just discovered. About a month ago I replaced the plastic fuel filter on my 86 300SDL because the engine was hesitating. This fixed the problem, I also purchased a primary fuel filter which I have yet to install ( didint know which one was bad ). So I have not driven the car in a bit and went out to start it and the battery is dead. So I jump the car and drive it most of the day ( ran fine no problems) Well I was about 30 miles from home when I was on the freeway going about 70 when the car started what I describe as hesitating. It would maintain 70 but it was almost like the engine was almost like a fuel / air starvation problem as the car seemed like it was hesitating to keep that speed. I get home and the car is running fine , engine will rev and run fine but a few days go by and I try to drive the car and it is doing the same thing this time at a lower speed. It will start out in first and right when it shifts to second the engine cuts power ( still runs and sounds fine ) but i cant accelerate because the car almost feels like it si going to stall. When I stop the engine runs fine and starts off fine. What should I check? I have not checked the air filter but where should I start? Any thoughts?

The "plastic" fuel filter is the primary. It doesn't stop much of anything.

You next task is to change the secondary filter..........up next to the head. Be sure that you completely fill it with fuel............after you muscle it into position............and before you tighten it with the retaining bolt............or you'll be back on here screaming that it won't start.

Fuel filters are a maintenance item on a diesel and should be replaced periodically............before one of them strands you...........