Camaro350z28

I've been having problems with my 97z for awhile now. Can never get it to run good at the track cause it always seems to miss at higher rpms... at first i figured opti, and tune up. Did everything brand new does the exact same thing. The thing is it only seems to miss under full throttle. Its not exactly a miss but kinda miss/bog kinda thing. And now ive recently noticed my check engine light does not work.. and i high a driver side cat converter code.. can a clogged cat possibly be my culprit the whole time?

If so.. i need to find a used one.. brand new cat a little expensive and my headers bolt directly to the cat..