My experience with a clogged cat came one snowy day when the P/U didn't want to go over 40 mph. When I got to my destination (short trip) I noticed the exhaust didn't even blow the loose snow around! Revved it up & felt almost nothing coming out the pipe...
Start & idle OK, but no power.
Disconnected tail pipe B4 muffler, and it STILL was running quiet with NO tail pipe or muffler, Kinda a hint there!
Cleaned it out for an emergency fix - LOTS of noise without tail pipe then! And all worked normally when reattached & test driven.
Many folks have noted that with a partially plugged one it'll tend to get REAL hot (glowing) after a drive, so that would be another sign.
With the "Wack" you say it took, the ceramic could have broken & jammed up the pie with loose pieces.
Hopefully it's an easy one to disconnect, so you can possibly look inside &/or test with it disconnected...
P.S. - The one on the P/U was SO clogged it wouldn't even rev up fully with the throttle floored!
Last edited by sailor; 11-10-2012 at 04:06 PM.