300E engine cuts out

[ON6666]

I have a 1988 300E auto which has done 160,000 kms.
The vehicle runs perfectly but has an annoying habit which no one has been able to fix.
Perhaps a dozen times a year the motor will cut out without warning at low speed, most often when I'm braking to go around a sharp corner.
It's potentially quite dangerous as the power steering becomes inoperative and the car is hard to steer.
Does anyone know what might be causing this and how it can be fixed?
Suggestions most welcome.

Frank