Hi all!

I am going nuts trying to figure out this vibration/ rattle that seems to be coming from under driver-side floorboard when at low idle (it goes away immediately upon putting the car in neutral). I am suspecting a bad cat, as my O2 sensors were shot, (since replaced), but after banging around the exhaust with a rubber mallet I couldn't hear anything rattling around inside the cats. What I did realize though, is that the driver side cat is up against the frame rail, and banging on it did cause a rattle against the frame. Is this normal placement of the cat?

Thanks guys!

Sam