I am shooting this problem and have now focused on the idle speed air valve area of the EM system. I have been thru the archvies and recall hearing that at idle when one removes the two pin connector on the idle air vale (which is connected to the idle speed controller) that the idle speed should increase. This does not happen in my case.

I have measure the following in relation --
-resistancs is perfect - 3-5 ohms.
-At idle the voltage accross the terminals is 1.25 volts and does not change or vary with rpm or engine temp.
-the MB engine manual has a test defined that looks at current thru this component and look for 700-1000 ma -- can this be possible???? A full amp of current thru these flimsy 14 ga wires???

At any rate - by my caclulations if the resistance is 3.5 ohms or so and the voltags is 1.25 volts -- the resulting current is about 300 ma or so and substantially under spec.

I have put this idle air valve on the bench and put 12v accross the terminals and noted the audible clicking expected.

Am I chasing a goose here???

FYI- my symtoms are long cranking when cold, very rough and slow idle to start until the air pump cuts out and/or something else changes and the idle smooths out. At high speed the car runs fine and does not smoke or miss.

Thanks.