weird sound for a few seconds

[mstar218]

Hi Ya'll,

I was driving around (Alero 2.4 automatic) without the radio on earlier and noticed a weird noise.
When I go 25mph or faster and let go of the gas pedal I get this funny noise for a few seconds. It's hard to tell if it's a grinding or hissing noise.

It doesn't do it when I'm stopped and step on the gas and then let go, but it also doesn't do it - after the initial few seconds - when I go down a hill and let go of the gas.

Any ideas what it could be or where I should start looking?