1991 300e,drove home from work today,noticed my idle was @1200-1500 RPM.Found EHA to be leaking.Could this cause this problem?Disconnected plug from what I believe to be the idle control valve(bosch part no.0 280 140 150) and idle returned to normal.Reconnected plug,idle still normal.Turned off ignition,restarted engine,idle speed slowly went to1500 RPM.Swapped valve from another car ...same results. Measured voltage across plug appears to be 4.5 volts.Any clues as to where this valve gets its signal voltage???? Any tests to trouble shoot this problem would be greatly appreciated!

Good info in more than one of these posts:

http://www.peachparts.com/shopforum/search.php?action=showresults&searchid=401052&sortby=lastpost&sortorder=descending

Mike,thanks for the info.I really appreciate it.Since my post ,I have cleaned all electrical connectors with electrowash.I have had normal idle since! I also must mention that I washed my engine a couple of days before this incident.I do this at least once a year to keep things tidy.I have never had any problems in the past.Iusually run the car for 45 minutes to dry things out , but I believe I may have only run it for 15 minutes this time. Any thoughts about using electrolitic grease on the connectors as some other manufacturers do? THANKS,DAN