This is quite normal for chevy fuel pumps to howl in the manner you are describing. It does not mean your fuel pump is going out. I have a 99 thats been doing the same thing forever.
I suggest you live with it if you can.
I also want to add that dealers suggest keeping your fuel tank over half full at all times to keep the pump from going bad.
Saturday, January 28th, 2006 AT 8:41 AM