Question? 300d dies when I let off pedal

[Brcline]

If anyone has any suggestions, I'd appreciate it. I've got a 76' mercedes 300d. It has decided to start dieing everytime I let off the accelerator. I am having to brake and let slowly off the pedal at the same time in order to slow down or stop. It typically idles fine when started and also once I stop at a light. At times it doesn't seem to be so touchy about it. Maybe at a slower speed/engine idle it tends to not die, but at a higher speed 45-70 it will die as soon as I barely let off the pedal. And sometimes it is just as touchy at a lower speed. Don't know if the idle linkage all of a sudden got out of whack or something else. I am running on veggie oil/diesel mix, but it will also do it on straight diesel, so I don't believe it's the fuel. I don't know though. Any help would be appreciated!

Thanks

[Diesel911]

Get a container (like a 1gal plastic gas container) of diesel fuel and run a seperate hose to the primary filter (change the filter if it looks clogged) and try running it like that and see if it changes the way your car runs. While the hood is open take a look at the linkage and see if something is not normal. Dose your car have the idle adjusting knob you can adjust from insid the car?
Dose your car have a mechanical or pneumatic Governor?

[Cr from Texas]

Plugged filters!