Well, I spent the day going through the diagnostic procedure on the Mercedes CD. It pinpointed the oxygen sensor, and indicated that the rest of the fuel injection system was OK.

I did not believe that the oxygen sensor could have such a large effect. An old post (by Larry Bible, I think) suggested monitoring EHA current while feeding different inputs into the oxygen sensor wire. Sure enough, grounding the wire gave my exact symptoms, while a slight positive voltage cured them.

So, Í'm off to see Paul in the morning, to pick up an oxygen sensor.

I find it amazing that the rest of the system works so well, after 20 years and 240,000 miles (380,000 km). These are tough cars.

Andrew
1989 190e 2.6