Rumbling and strange sound from the rear

I have a 2001 Pontiac Bonneville, every time i start the car theres a wierd sound and rumbling from the back of the car. Kinda like like a humb only stronger and louder, at first i thought this was the fuel pump doing something but i have no idea. Anybody know what this could be. Also where the heck is my radio attenna? Anybody know this? Thanks.

I have a 2001 Pontiac Bonneville, every time i start the car theres a wierd sound and rumbling from the back of the car. Kinda like like a humb only stronger and louder, at first i thought this was the fuel pump doing something but i have no idea. Anybody know what this could be. Also where the heck is my radio attenna? Anybody know this? Thanks.

Hi spike, I have similiar noise,(2000 sle) I think it is the ride control.(if equipped)This noise last 10 - 15 seconds. Antenna front windshield.

if you have the auto-level suspension, I agree with cool, it's your compressor. He's also correct about your antenna, it's in the windshield.

Thanks guys, now it makes sence. I was worried at first lol. Kool spot for the atenna though, its inside or on the side or what, i cant see it lol. Thanks again.