See if the idle relay is working. Push the electrical connector on the idle valve back to expose the pins. Put a meter on the pins and see what voltage the idle relay is sending. If it's zero, you have a dead relay. If it's around 3.5-4V, the relay is trying to control the idle and you need to look for air leaks. Spray some brake clean around the idle air tubes and see if the idle speed changes.

Good luck,

CT

__________________
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