You would think it would throw a code and its fairly rare, but a crumbling cat will cause something like that as well. It can also be random as large chunks could shift around and block the exhaust more or less. They will also usually rattle enough to make you wonder what's about to fall off the car, but not always.
2008 Acura TL Type S - 140k
2003 Honda Accord V6 - 220k
2000 Honda Accord I4 - 290k
Current Oil - Milesyn SXR5W20/5W30
Current Filter - Partsmaster 61334