P0420 Honda -element

Question

Okay 2006 Honda element I had two codes PO420 cat converter efficiency below threshold bank 1. and PO302 Cylinder 2 misfire. Change O2 senor back/ rear and replaced spark plugs. Also switch coil to confirm its not the coil bad, light went off and i didn't have to clear the codes. after 30 minutes of driving engine light came back on.

Answer 1

Misfire code condition would surely shorten the life of the catalytic convertor, If the misfire was allowed to occur long enough damage to the catalytic convertor would definetly occur

 The purpose of the CK ENG LT is to protect the catalytic convertor and catalytic is to protect the enviroment. Having a misfire would only send raw fuel into the catalytic this would damage the catalytic at a faster rate.