126 Idle Problem 380SE
 

I had an extensive tuneup done on my 85 380SE after it sat for a while with little use. Built up a lot of carbon, so I had to drive the car about 300 miles and get the tech to tweak it a lot to pass emissions. I've since been using it regularly. Ever since the work, the idle is erratic. Sometimes it idles at 600rpms and sometimes it jumps to 1600-1800rpms. It slams into gear pretty hard from park and I worry the tranny will be damaged. This happened once before and it was the OVP fuse. Fuse looks fine now. I'd hate to go for a new Idle Control Module - I've put a lot of $$ in the car lately. It's just coming up on the 100K mark if that makes a difference.

Any suggestions folks?

Check for obvious vacuum leaks. The mechanic might have yanked something loose while working on it.

went through the same thing. here's what ultimately
solved my problem: http://benz-store.com/idle_speed_control_unit.html

it's rebuilt and adjustable. you'll also want to check your
air slide valve to make sure it's working and check resistance.
should be 8-12 ohms. if it sat, the old junk may be gumming up the slide. clean it out with carb cleaner.