I have a 1984 300cd and the gas pedal (accelerator) does not work any more. I thought that my car was sluggish because it needed a diesel purge (did that). Now the gas pedal does nothing. I tried to manually push the control linkage assembly and it seems to stick or get hung up. I think that I need a vacuum valve levers. Is there any thing else that would "loosen up" this problem? Thank you in advance for your help. Mathieu 1984 300cd turbo 314,000 miles