Hello, new to the mercedes family and to the sight but eager to fix and drive my newly acquired 1980 300sd W116. I have searched this and a few other sights to try to understand my issues and here they are: preheated and cycled the plugs for about 2 days forgot and left the key on; transmission will not allow the car to shift until you let off the gas (diesel pedal) and ease back into it; and of course the heat and ac. The car is a 1980 300sd 225k+ odo died, 3rd owner Chassis #12 018523, china blue?(navy blue) The car ran fine before the key incident. The car will turn the engine it just will not fire injectors? Previous owner thought the trans issue maybe vacuum but from what I have read it may be due for a rebuild. I do need heat because Indiana can get quite chilly. I love the way the car looks and drives and my 2 year old daughter just loves to play in it. Sorry for being so long winded and thanks for giving me the opportunity to post.