Have Codes PO146 andPO420 Replaced 1 Oxygen Sensor Lite is Still On

Question

Lite Went Off After Driving For About 75 Miles Drove To Get Smogged He Told It Had The Same Two Codes And The Gas Cap Failed Lites Been On Every Since I Left Smog Shop What Should I Replace? Car Is A 97 With 179,000 Miles

Answer 1

P0146 H02S insufficient activity bank 1 sensor 3

P0420 Catalytic below efficiency bank 1

The 02 sensor are fused so if the fuse goes out  you dont have a 02 heater circuit. In the engine fuse box listed as ENG fuse 5 which is a 20 amp fuse. Check 02 sensor sensor 3 on bank 1, make sure the harness is not broken or got melted by the exhaust, It is also good to check for vacuum leaks,,The worst scenerio is you need a catalytic,