I purchased an 88 300 TE with 272 k miles on it in August and its been fine for me until recently with the cold weather. It won't start but gives every impression it wants to. Plenty of crank and a sounds like its ready but won't hold the rpm s. When I was finally able to get it going the temperature outside had risen significantly but the car felt like it was running on 3 cylinders. My mechanic, who's not a big Mercedes guy, seems to think that a block heater should resolve the problem but that assumes I plug it in at every stop. I noticed that a cold start valve is an available part but don't have a clue. Maybe just a tune up? Any thoughts would be greatly appreciated. By the way, it will remain cold in these parts of Idaho until April.