This sounds VERY similar to my 300E's problem!

I disconnected the EHA. Cold start was horrible, but the
running performance was GREAT once the engine had some
temp/heat.

I next looked into sensors, and found (so far) a scratchy
Air Flow Sensor. The Overvoltage and Altitude Compensation
MAY have something to do with it.

If you don't want to spend the money for an M-B CD set, try
you library, and look for chapter 5 of "Fuel Injector &
Electronic Engine Controls" for 1988-90 (European cars,
Chilton P/N 8120.)