Mercedes Benz repair: grades and my 80 300 SD, cold weather problems, banjo bolt

Question
I have a few problems with my 80 300 SD.  The first is on colder days (25-40F, this is so Cal) when I have to climb hills it will not accelerate.  It's almost like there's a governor on the engine that keeps it from getting fuel and it seems to be auto trans related.  The same grade on a warmer day is no problem.  The previous owner mentioned something about the adjustable transmission but did't give any real details.  I have replaced the fuel filters and am using an additive to prevent cold weather problems (fuel separation, water, etc.).  The second is if the driver's door is not locked while driving, the engine doesn't shut off with the key.  Could the vacuum leak be in the left rear door and do I need to replace the vacuum hoses there along with the front?  The last is that I have no heat from my heater/defroster and the fan only works when the defroster is on.  Thank you for any assistance you can give me.

Answer
The door lock issue sounds like a vacuum leak in the door.

The cold issue could be plugged filters, plugged ALDA pressure feed line or a fuel line leak.

Banjo Bolt
http://www.mercedesshop.com/shopforum/showthread.php?p=733935&posted=1#post73393...

Fuel Delivery:
http://www.mercedesshop.com/shopforum/showthread.php?t=142399

Diesel Injection:
http://www.mercedesshop.com/shopforum/showthread.php?t=142405