When I was inspecting my cat, I had this piece of pipe "fall" in there and had a sledgehammer "slip" onto the pipe and break it up. I'm so accident prone. <img src="/forums/images/graemlins/lol.gif" alt="" /> It won't throw a code cause the sensor is before the O2. On the newer ones with O2's before and after, the rear checks for a different reading then the front. That's how the O2 can tell if the cat is plugged/bad.

Blacktero: 90 Montero Lwb V6 RS Model. 16" Toyota Alloy Rims, Dual Bouncy's; Gen II Front Rotors & Calipers; Rear LSD

Sraider: 87 Raider 2.6 base. Work yet to be done.