O2 Sensor Noise? 00 Tahoe

I have had a metallic grinding noise at around 1100 RPM's. Originally I thought it was a heat shield but I took it to a Midas and they said the O2 sensor was causing the noise and they could replace it for $230. Does that sound right?

Sounds weird, i've never heard of an O2 sensor making noise...I would imagine its your Cat not sensor...Take a long screwdriver and place the metal end on your exhaust manifold, block, or Cat and hold the other end to your ear...That will send the vibrations to ear pin pointing the cause...Good Luck