Noisy Fuel Pump

Just noticed that my 96 Buick PA fuel pump is very loud with the ignition key on without starting the engine. I have never noticed this before. I assumedeven with it it being loud, pressure would build up and it would cycle off - it doesn't seem to.

I don't notice the noise with the engine running. Also, when I shut off the engine and immediately move the key all the way on - I don't hear the pump.

Is this typical? Is the pump going bad? Is there a pressure switch I should be looking at?

Thanks, Rick

No pressure switch on the fuel system. When is the last time you changed the fuel filter?