I just purchased a 1987 300E with a rebuilt motor, but it has problems with idling in drive/reverse when warm. It idles about 500-700 RPM and has a clear miss in the idle, and starting off it hesitates pretty badly. Once underway, it's smooth and strong, though - no miss at all.
Idling in drive also produces a small blip and it idles close to 1000 RPM.
I suspect that there are some sensors or the like that need to be cleaned and/or replaced, but I am not sure where they are at. The layout on the engine control system is pretty different from the Range Rover I am accustomed to. I'd like to get some guidance on where the sensors are located, and what suspect(s) might be most likely.
I have already checked the ignition wires and for vacuum leaks and it appears OK. I am assuming that the rubber line from the valve cover to the top of the air cleaner is only a breather, as it is a little loose, but I am assuming since it is a breather, it is OK. Most of that stuff is new.
Do I need to remove the air cleaner assembly to get to the idle control parts and/or is there an idle adjustment screw I can simply crank up a bit?
Also, any suggestions on a good, affordable source for parts would be great.