My son's '86 300E was doing the same thing, dying when slowing down or going into a turn. Wasn't every time, just enough to make him unsure of taking the car to work/school and back. I troubleshot and tried various parts: OVP, Fuel Pump relay, Idle Control Relay, etc. I finally duplicated the failure one day at home, it turned out to be the distributor cap. I ordered an new one from parts lane, and it has never cut out or died since. Just my .02 worth.