I have a 78 240D manual.

It does not shut off when turned off, I have to stall it out or push the red stop button under the hood. That is annoying, but I think I can live with it.

But this morning on the way into work, I went to shift and the throttle continued to rev at the same level after I pushed the clutch in. the revs didn't come back down. It continued like this until I parked the car.

It isn't a terrible problem because once I shift, the transmission brings the throttle back down to normal revs and it drives normally.

Also, it doesn't open up by itself, just stays where I last pushed it to.

What is this? Vacuum pump? Is it likely to get worse? I plan on driving this 1900 miles tomorrow to Oklahoma and back to Michigan.

Thanks for the help.

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81 300D 250K (sold)
79 240D 200k
83 Volvo Station Wagon (282k)