hello gang, this is a new post on stalling of my wifes 90 model after having some bad gas trouble,a new problem has arisen,when we decelerate it will about half the time, drop below 500rpm and stall. I have paid close attention to the tack when slowing down and some times it stalls when falling and at other time it catches itself and it jumps back to life but it sounds as if it stalled and relit( as if you just started the car.) the potentiometer is only a year old I wonder do they go out off adjustment.

I had the same issue in my '91 and the 380sl. You will find some people talking about the crank sensor which made the most sense to me.
A local 76 station sells 100 octane fuel. A few times I added about 30% of that to a tank of gas and the problem instantly vanished. I know this does nothing to help you but I wanted you to know that you are not alone.

I think it's very odd that no one has an answer for this and also strange that more people are not experiencing this issue. I have this problem in my 420sel and the 380sl and have had two very well respected shops try to fix with no sucess.