83 240D vacuum problem
 

Hello,

I have a '83 240D that I am about ready to sell. It's having a problem shifting down while going uphills or when the gas pedal is to the floor or almost to the floor and I am trying to accelerate fast. When I go uphills, or attempt to accelerate fast (not really "fast" when talking about a 240D), the car will upshift at certain speeds no matter how big the hill or how far the accelerator pedal is pushed down and it upshifts too quickly, so I have to manually shift to a lower gear. The car also continues to run for about two to three seconds after the ignition is off and the power door locks are hesitant to unlock after I unlock the driver's door lock. I was told that there are three vacuum controls, the ignition, the transmission, and the door locks. Is there any way I could find out what the problem is without spending $80/hour or higher for a mechanic to look at it? Thanks for the help.

Sounds like the classic W123 vacuum leak. These vacuum systems are not really separate, they all get their vacuum from the vacuum pump on the front of the engine. There is a fairly large vacuum line from this pump to the brake booster with some smaller lines branching off. A leak anyplace in the system can affect everything else. Do a search on vacuum leak and you will find lots of info about chasing down these leaks, it's not hard, just tedious, and usually cheap to fix. I spent about 4 hours looking for one last week.