Just drove the car. It is worse than before (now it has poor idle and acceleration), but they said the poor idle may be due to putting on a bad set of new wires. They will put on another new set tomorrow. They said that the acceleration is probably due to a faulty air flow meter.

They told me that you have to buy the whole air flow meter from Mercedes, not just the potentiometer. Are you sure you can get an official Mercedes potentiometer separately?

So tomorrow, a 3rd set of wires and then discussion of the Air Flow Meter subject.