Whistling Whinning fuel pump
 

O.k. guys, need some help on this one. 2001 Explorer. 4.0 2wd. I haven't driven it in about six weeks. Drove to work and heard a whistling. Thought vacc. leak but none found. Poor accel. and whistling gets louder on accel.. Replaced fuel filter last weekend and no change in accel. and noise continues. And I hear a clicking sound from underneath when I'm stopped and then as I accel the whistling starts. And gets louder as I press pedal. No hard start. Starts right up, but I don't hear the pump at key on. The only time I heard the pump was after I replaced the filter and of course it pumped. Other than that when I get in and turn key I dont hear a thing. But it starts right up. In park at idle no sound and I've even sat and reved the engine. So,, what to do? Shop wants 660 to replace. Oreilys sells a pump for around 120. And I can attempt the replacement myself with the help of a shadetree mech. Any suggestions?

Oh yes, these are a driveway classic repair. It'll require getting the car up off the ground a bit, dropping the tank, and depending on how far up the car is, either doing it in car (which is right behind where the rear spings attach to the frame at the box), or disconnecting everythign and dragging it out.
One word of advice; some of the aftermarket pumps don't last very long, so get a better quality one, if you can.