2000 Chevy Malibu Engine dies

Electrical problem
2000 Chevy Malibu V6 Front Wheel Drive Automatic 80,000 miles

I have a 2000 Malibu that has quit running numerous times on the road. When this happens all power is gone. The engine quits, interior lights, dash lights and headlights go out and when you get the car to a stop and try to restart it it acts as if the battery has been removed. It will not turn over. After sitting for 10 or 15 minutes, it will start and run ok until the next time it happens. Initially this happened when the fuel level approached a quarter of a tank of gas, but now it seems to happen when the level is above that and the frequency of it dieing is more often that it initially was. It is currently at the dealer, the diagnostic tab is growing and they cant find a reason. They supposedly dropped the tank and have checked the fuel pump and sending unit and found nothing. There are no codes to indicate what caused it to die and they have been unable to duplicate the problem. I went on line and there are numerous reports of this for this vehicle, but again nothing with regard as to what is causing it.