The rough-idle-and-die is one of the most perplexing problems of the 300E. I gave up and sold mine.

It sounds like the idle valve is a culprit. Are you getting current to the valve, though?

Don't try to set the idle by farting around with the mixture. Since you don't have lambda, you can use the current flow to the EHA to set the mixture. Once you have a good idle system and the right mixture, the idle speed will take care of itself.

Lots of post on measuring EHA current, and your friend should be able to get the specs for your car.

__________________
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