1998 Ford Mustang mileage: 164,000. We are looking at purchasing this car. While test-driving this vehicle, we noticed a rather loud whirring sound coming from the back of the car. This sound continued whether it was moving or stopped. Our first guess was the fuel pump and in fact was confirmed by the mechanic; the sales person says that Ford fuel pumps are typically loud and the fact that it is a hatchback amplifies the sound. Personally, I have driven other Ford Mustangs and have never heard the fuel pump. Is this in fact typical of Ford fuel pumps or should we be concerned about this sound? Thank you for any information you can provide.