1997 Ford Explorer Frod Sport Try Start Turn Ignition Position Wait Seconds

I have a 1997 frod explorer sport. When I try to start it I have to turn the ignition to the start position and wait a few seconds about four or five times while i pump the gas each time. Then hopefully it will start before the battery dies. It does not cut out at all while driving. It has progressivley gotten worse. i can hear the fuel pump turn on when I turn the key to the on position.