300sd just died

[moxwell]

Hello I have an 83 300sd which had a rough idle when stopped at a light however once the pedal is pressed it smooths out, today the car began to hesitate and it stumbled a little and then just died. it cranks and the engine turns over and I am able to rev it up once it turns over but once i let off the throttle it just dies. The car at times stays on and it runs a little but then it just does not accelerate and it just shuts down. The car has just over 135,000 miles. any help is greatly appreciated.