very choppy idle
 

my 1980 300d has been giving me grief lately. as i pull up to a traffic light, after a couple seconds the engine starts shaking at a much higher level, and then shuts off. someone suggested it was the fuel pump, but i need a second opinion. what say you ?

Maybe fuel
 

I had similar symptoms in my 82. Refilled with Speedway fuel and all is well.

what's speedway ? is that a brand or higher octane ?

Speedway is Marathon Oil's brand. Ran poorly on BP's diesel.

Water?
 

The Speedway station I normally use is on a high traffic road. The BP station is on a much less traveled road. We had a VERY wet spring here in Detroit, (second wettest on record). I wonder if the BP station had some water in their fuel tanks? I mean it was like I flipped a switch. When the BP fuel was gone and I refilled with my normal Speedway fuel the car ran smooth again. I agree that is probably has little to do with the brand. Maybe it was just water in the fuel...?

ok well say it wasn't the fuel itself.. my car will start but when i try to put it in gear it just shuts off. if i rev the engine though, the car stays on. wtf !?!

If the car starts easily it isn't air in the lines. If it will run ok at higher speeds, it probably isn't the delivery pump, or the injector pump. That leaves fuel quality, or a dirty fuel filter, or maybe a combination of both

Could the idle just be set too low?