more information please...
1. what make model year is the car?
2. does the noise remain the same when reving the engine?
3.is there noise with the motor off and the ignition on?
4. is the car fuel injected?
5. ford has rfi producing fuel pumps in the gas tank the dealer can fix them
6. many more questions but you need to provide as much information so we arm chair troubleshooters have something to work with
good luck firstname.lastname@example.org