85 300TD poor fuel economy

[Benzi]

I have owned the vehicle for 6 years. 120,000 miles on car. I only get about 20 MPG have always felt that it should do considerably better than that and after reading so many threads and hearing what others are getting I feel there may be some problem.

Also I live in S.W. Mo. in the Ozarks I live on a steep road leading out of my Driveway It used to be that sometimes when the weather was cool I could take off out of my Drive and cruise straight up the hill. but for the most part it would not climb the hill other than with my foot jammed to the floor it would literally crawl up the hill, if you were walking at a slow pace you would pass her up very annoying. If I went down the hill first and got a bit of a run at it once the Turbo kicked in it would climb right up. it seems like it is not getting enough air or something possibly for the turbo to kick in sooner when I leave my drive but I dont know.

One more thing that I always wondered about is the shifting of the transmission I would have thought that I could put the car in the lowest gear and just climb right out of my Driveway but if I sit in my drive and shift it to low it has absolutely no effect. however if I am rolling say before I start the climb and shift down than it will drop down in to the lower gear and climb like it should could there be a tranny problem? no problems out on the road!

I know this is an aweful lot but I am hoping someone can help me. Havent had much luck with mechanics working on it. figuring out it's problems. Myself and my family love this car but with this problem all along and some other things now the ACC is out we are actually thinking about selling the beauty Had someone looking at and driving her the other day and they thought there was a simple fix for both problems that I have stated the mpg and the power out of my drive problem please help!