Thanks Gavinbr,

I did actually check the things you mentioned. I was having a stalling problem and thought (mistakenly) that the pot would fix it. So I replaced the pot and it didn't cure the problem.

MB tech later looked at the car and found the EHA was failing. So he replaced it, put my old pot back on the car, and adjusted it.

So it is definitely an issue with the pot/air flow meter assembly. I'm sure if I swap the air flow meter with a new one, the problem will go away. The tech spent lots of time adjusting the pot (I gave him the documents you refer to below) but we just couldn't get it right. He made the comment that he has tried adjusting them over the years but found that replacing the whole unit is the best thing to do.

I did mark the pot when I removed it, but even a minor adjustment seems to make quite a difference. Even when I put it back according to my markings, I couldn't get it exactly right.

Are there any adjustments I will disturb (mixture?) by just swapping the entire air flow meter/pot assembly with a new one?

When you say you "replaced the AFM" are you just referring to the potentiometer (little black electronic thing) or the entire air meter assembly (big metal thing with round butterfly valve)?

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