1993 730i Electrical Problem - O2 Sensors

Has anyone come across a problem with BMW V8 730/530 engine (Mine is 1993 730i) whereby the following happens: u travel 150 miles (or 5 miles- only happens with hot engine) no problem - stop briefly - car restarts and cuts out - can be restarted and with patience can be got to rev to 3,000+ revs. Then may or may not complete home leg of trip. When driving the car may splutter intermittently and coaxing with much pumping of accellerator may clear the problem. Idle motor has been replaced, 02 sensors replaced, ECU reprogrammed - problem comes back. It is fuel supply related as opposed to ignition in our opinion. This problem is intermittent and cannot be picked up on normal diagnostic gear as 3 Main Dealers have informed me to my cost. My auto electrician has identified that the problem is with an undetermined spike blowing oxy sensors?? If not solved soon this car will become a very comfortable henhouse and I will be ruined. All suggestions much appreciated