The 500 SEC, 1982, that I purchased was driving good then I noticed that at lower sppeds, like in the city, the car stumbles in thrid gear. It doesn't do it on the highway. The previous owner says its a vacume line problem. Can anyone help?
You mean changing into third, changing out of third, accelerating in third, or cruising in third....etcetera? maybe you should be more specific. Anyhow, the filters in these transmissions should be the first thing to be changed when you get the car.