Well I've done a little tinkering and this is what I have so far. I cleaned the idle control valve, and it made it idle up much quicker when unplugged, but doesn't make any difference when it's plugged in. When cold (and plugged in), it does not idle up much at all, and the idle is really lumpy. When I unplug it (cold) it idles up where it's supposed to be and runs smooth as can be. As soon as I plug it back in, it stumbles really bad and acts like it's gonna die but doesn't. So is this a simple bad idle control valve?? Or could the problem be somewhere else which is affecting the ICV? Where does that plug on the front of the ICV originate? Could where that signal or current originates not be getting to the ICV? How can I test all this?
'86 420SE Euro
904 Midnight Blue, Gray Velour
Dad bought it new, now I own it.
"A Mercedes-Benz is like a fine wine, it only gets better with age."