I'm 95% sure its your OVP then. I've never experienced an OVP issue while the car is under acceleration above 20mph. It always stalls when cruising or braking coming to a stop at a light for instance.
Should be an easy swap. It may also explain any other odd running conditions too if you have any.
I've ran into the stalling issue on both my cars. (I got my wagon cheap for this exact ISSUE LOL, no kidding. PO just couldn't seem to figure out why it was stalling and with a newborn, he didn't feel safe). I browsed this forum and found said holy grail ovp and it instantly fixed it.
With my 260E a few years later, I came with an OVP in hand ready at purchase location as I saw the ABS was on. Instantly fixed that on the spot.
