This car actually has a 16 pin diagnostic connector, cleverly concealed under a cover on the right side of the firewall with the hood light switch sticking out of it. So I dug out my impulse counter and pulled the following codes:

CIS:

10 - Idle speed and throttle switch implausibel
4 - Air flow pot current implausible
18 - Current to idle speed valve implausible

Ignition

17 - Crankshaft position sensor defective

I cleared all codes and drove the car. The only one that returned was the 17. Not sure what this would have to do with the idle problem, but it's possible that this has screwed up the RPM signal.

__________________
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