2004 chevy tahoe v8 z71 has on the underside middle front of car a rattling noise at low speeds during acceleration. Sounds more like a piece of metal rolling in a coffee can. Its a metal clanking sound like loose piece of metal inside some metal compartment. I cannot see any loose heat shields or loose bushings. Read about something with an O2 sensor does not make sense. Someone suggested possibly the catylitic converter honeycomb breaks down causing a rattling metal clanking sound. Has anyone heard of this issue or any suggestions as to what is causing this?