... 87 300D doesn't shut off when I turn the key to "0" position. I shut off the engine manually, and am assuming I can do this and still successfully start up and drive again (either that or I'll be in trouble when I go to leave work at 2 am). I'm taking it into the mechanic to have it looked at on Wed. Just so I'm not completely ignorant to what's happening to my car, could someone debrief me as to why this is happening? He mentioned that it may be a vaccuum failure.

Feeling very frustrated at my lack of knowledge ...

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