Are you just talking about the large heat shield that goes over the whole O2 sensor area. (the O2 sensor that is close to the "TOD" stamp), or is there another smaller shield that is just covering the O2 sensor?
I was underneath the beast hitting further down the pipe and was able to hear the rattle so I know its coming from that area, but after holding everything, the only thing that seems to lessen the noise is if I hold the O2 sensor. It almost sounds like there is something dangling in the inside of the pipe and rattling.
I also have that stupid PV2 muffler so that probably adds to the vibration.
IIRC, there are two or three smaller shields within the scope of the exhaust system, & they're known to rust through the clamp & start rattling.
I guess I will just start removing them till the rattle goes away. Then start putting them back on.
Good idea???