I have a 1992 230TE. Only had the car one year. Body and underneath is excellent so I think that it has been looked after. When I come to a hill the power drops off dramatically and I can only go at about 45 MPH. I have noticed that the idle valve?? is not connected to its wiring plug. When I plug it in, the car will start but will not idle and stalls. I have fitted a new fuel filter and ignition leads, but it has made no difference at all. This is my first Mercedes so do not know much about them. Can anyone Help??