I took I think it was cblots advice and hit the cat with a hammer to see if anything rattled. What I got was a sound sort of like a pinball rolling in a metal can. Is this what a bad cat sounds like? Also I checked the pipes going all the way to the engine, as well as i could since my ramps are lost somewhere, and checked to see if anything felt loose. Just a little ways up from the cat were the pipe starts to bend back up it was really lose. I could slide the pipe? up and down. Is this the heat sheild for the pipe going up? I could see that being the source of the rattling as for the exhuast coming up under the car i don't know, didn't feel any holes, maybe it was just the wind? If it does turn out to be a bad cat anyone have any good suggestions of were to get a new one and how easy are they to replace, diy job? This is my first car so i don't know everything about them yet but luckily for me my best freinds dad use to work on these for a living. Thanks for any advice.