1999 Chevy Suburban ENGINE START UP

WHEN I START THE ENGINE IT TAKES A COUPLE EXTRA CRANKS TO GET GOING. I REPLACED THE FUEL FILTER AND SPARK PLUGS WITH NO CHANGE. IT WILL START RIGHT AWAY IF IT DOESN'T SET ONCE IT IS LEFT OFF FOR A WHILE THE SAME THING HAPPENS. DOES THIS MEAN THE FUEL PUMP IS GOING OUT GRADUALLY?OR DO FUEL PUMPS JUST QUIT ALL OF A SUDDEN? WHEN I TRY TO TOP OFF THE TANK , THE GAS PUMP AT THE STATION DOESN'T RELEASE AND FUEL COMES OUT FROM THE TOP OF THE TANK. DO I HAVE A PRESSURE PROBLEM IN THE TANK? I MAY HAVE A LEAK IN A GASKET BUT IF I AM GOING TO TAKE THE TANK DOWN I WAS WONDERING IF I SHOULD REPLACE THE PUMP.