I have had my 1992 300 CE (92K miles) for 2 months now and love it. I would like to fix an idle problem however. It will idle properly (750 rpm) perhaps 25% of the time. Usually, it will instead idle around 1000-1200 rpm, in drive, with the brake applied. Occasionally, it will idle as high as 1500 rpm, and when you shift to neutral, it goes to 2000 rpm. As part of my initial maintenance "once over" on the car, the car has new plugs, cap, rotor, fuel filter. Air filter looked new. I've run 1 bottle of Techron thru the car.

Thanks in advance for any tips. Just placed my order for the W124 CD service manual too!