Humming/Whirring Sound Under Engine

[Tyberius777]

Hello,

I have a 2002 Mazda Tribute that I bought used.
I have been LOVING this vehicle especially since it is the LX option and therefore has the 4 wheel drive option.

Having 117,000 miles on it of course I was definitely expecting to have some issues sooner or later with it. After all it IS mechanical haha.

Anyway, because it is hard to explain I am also putting a link here so you can hear what I'm hearing and WHEN I'm hearing it as well.

http://youtu.be/XwcMI-Cki1Q

I can best describe the sound as whirring and it happens for a split second when simply turning the key to the on position before even starting. After starting the vehicle the sound starts again and with a very noticable and continual whirring or whining sound. The sound will disappear once and a while while driving but almost always comes back. It will completely stop once I get over about 30 mph but will return once I start going slow again near 20 mph or so.

When I get under the car to listen, the sound is definitely in the back area of the vehicle a little in front of the back wheels.

Any help with this problem would be most appreciated thanks in advance!

[timd]

Fuel pump! When you turn the key on but not start the engine, the fuel pump turns on and then stops.