I had the same problem. Barring anything wrong with the vacuum shutoff valve on the IP, you're likely to find a vacuum leak to be the cause of your troubles there, or I suppose a weak pump...read on...

I read recently in another thread where MB should've issued a Mity-Vac along with the first aid kit, which I think is not far from the truth... For starters, check here for a good vacuum check-up procedure and go from there...

If you've got oil in your ignition switch, you've likely got oil in your vacuum lines, since it is vacuum control of the IP shutoff valve by way of the ignition switch that shuts the engine down. It is not "another thing entirely", but likely symptomatic of the SAME problem.

When vacuum was once again tight, I found my transmission shifting a little soft for me as well where it had been shifting hard before, having been hindered by a vacuum leak that resulted in a non-functioning vacuum modulator. I had to adjust the modulator slightly as well as the throttle pressure cable (aka bowden cable) to get the shift quality and timing (respectively) as I like it. You may have the slide type throttle pressure adjustment on an '83...I'm not sure. In any event, adjustments for shift timng & quality are VERY easy to do...check here for instructions.

Anyway, have fun. Be sure and let us know when you find that EGR...

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-Ken Harris
1984 Mercedes 300SD
2001 VW Passat 1.8T
2004 Harley Davidson FLHRSI
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