Quote:
Originally Posted by m5mulli
Would any of you great people with an m103 be willing to take the same readings on the throttle position sensor?
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Had the exact same problem as you with my 1990 300SE, with the only difference it solved it self
after I replaced the head gasket. And here is the weird part: after the first start up with the new head gasket the idle immediately went up to 1100rpm and after being warmed continued to 1800rpm like it always did, stayed at 1800 rpm for a few seconds and I heard a bang, idle immediately dropped to 700rpm. And that's where it stayed, the idle was perfect for almost 1.5 years, unfortunately the high idle has returned on occasion after I washed the engine bay a month ago. But only for the first 10/15 minutes after the first start up in the morning.
Changed or checked every part that could have caused the high idle, nothing fixed it or would even change the idle speed. Just as in your case if I disconnected the icv the idle would drop to 1100 and to 800/700 in gear...
Good luck.