P0420 code but Cats tested to be good, should i try to replace oxygen sensors

What is your question?

Car hesitates on acceleration, hard starting. Replaced fuel filter, rebuilt trans, new IAT MAF and MAP sensors. Replaced spark plugs, checked for exhaust and vacuum leaks.

What makes this problem better or worse?

Runs worse with A/C on and code comes back on quicker.

How long has your 2001 Isuzu Rodeo had this problem?

A couple months, but the car was sitting for a few months before the trans got rebuilt