Well I replaced the airflow sensor pot. and yesterday I set it .65v idle with motor warmed up.
The fact that there were changes in the running of the motor from removal to replacement leads me to believe that the sensor is working, so I guess I'm back to square one. I need to try a replacement ecu.
I'll check ebay etc. the Bosch number is 0280 800 212 and the MB number is 005 545 8032. If anyone out there has one for sale please let me know.

Thanks for all those who helped me.
Michael