What will cause my car to just shut off while driving at an average speed? on 2000 Pontiac Grand Prix

It only shuts off when the car is in motion. When it shuts off a wierd sound comes from near the back of the car. It use to would start right back up while in neutral while it's still rolling but now I must put it in park and to restart. It doesn't start right up it takes a few minutes and few tries and the engine will turn on over and attempt to start and then after a few it will start up.

Asked by for the 2000 Pontiac Grand Prix
sounds like a failing fuel pump. have it checked at a shop and get a bid.