Some of this is coming back to me from my 300E. I believe that in addition to the throttle position switch, your car also has a potentiometer that provides the brain with information about the depression of the sensor plate. If this is screwed up and sending a bogus signal to the brain, it could cause the troubles you describe.

There should be a test for this in your Mitchel documentation.

You used to be able to buy the pot from Bosch, but now I believe that you have to buy the entire mixture control unit.

__________________
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