93 f150 4.9l dual tanks, just recently ive been hearing a weird buzzing noise that i just noticed yesterday and i decided to switch from the front tank to the rear and the buzzing noise stopped so i used the rear tank. the front one was just below 1/4 of a tank of gas. then today im on the rear tank and get to about the same spot 1/4 tank of gas and i hear the same nosie. the fuel pumps are loud. so then i go to gas station then put in $20 and got 3/4 on the front tank and im still hearing the buzzing noise in the pump. does any1 know what this could mean?

 

...if this sound is happening right when you turn the ignition switch to the on position before you start the truck then yes it is the fuel pump. I don't know if yours is dying. My fuel pump made that noise for an extended period of time before finally giving out. My new fuel pump i have now does not make that noise anymore. Hope this helps...