Hi, I have an '85 300d 123 sedan. I have a vacuum problem, which works like this: Unless I lock the driver's door, which locks all the doors, the engine won't shut down, and the transmission shifts roughly. Lock the doors, and everything is good. So I'm concluding that the vacuum pump is okay, but there's a leak somewhere in the door locking system. I have a couple wrecked 123's in my back lot, so could switch out parts without much trouble or expense. I would appreciate any pointers from someone who has dealt with this before.
Thanks in advance.
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