This is a tough one from a distance.

It sounds like you have lost either the OVP relay or the lambda/idle relay. This would cause a both a high idle and a loss of enrichment.

Did you work on something before this happened? Or did it develop gradually? Sorry, I had to ask.

If you disconnect the idle air valve at the front of the engine, does the idle change? If you don't know how to do this, you need to find a shop that understands these cars.

Good luck.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe