Even a completely inop 02 sensor cannot cause the mixture to go outside the
fuel map for this engine enough to cause a cat failure and without affecting
performance and setting a code as well.

if a cat is that plugged you would have poor drivablity and if you punch it
it would make a hissing noise out of exhaust is the codefor lean or rich
exhaust what is the O2 sensor reading if you dont know take it some where
to find out it will cost you less that throwing parts at it ie:just cus it
has that code it is not always the sensors falt lick lean could be a vacuum
leak, intake leak, ect.