Oops... yes it has a somewhat rough idle. it does not usually stall, but acts as if it would... I had the vacuum disconnected to the cabin and did not find any improvement.
Just followed along here
PeachPartsWiki: Isolating Vacuum Leaks
That is a really neat way to find vacuum leaks... I doubt I would ever have found it any other way!!!
And found the big funnel shaped rubber, or square gasket at the bottom of the (what is the throttle plate assembly called by Mercedes?) funnel where it connects to the intake manifold runners.... That is gonna be a bit of a job getting it all apart.... anyway when squirting some ether there, it takes a moment then the O2 sensor jumps from about .15 =>.9 and sometimes over 1 volt..
Does that sound like I have found the culprit? After lunch I will re test..
Considering that I am now likely taking the whole fuel distribution assembly off, are there other things I should do to while I am in there?