try disconnecting the plug from the idle valve and see if it makes changes to the idle speed.that valve is normally closed and the ecu opens it.if unplugging makes no change then you have a large vacuum leak.

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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
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