Catalyst System Efficiency Below Threshold (Bank 1) chevy travse 2011

Question

how would I repair the issue ?
also how would I know what onw is the problem cause when I google it it says replace coils replace spark plugs it only happen after we did a oil change !!!! please help

Answer 1

P0420 Catalytic below threshold Bank 1

Check the oil level and correct  , this code after a oil change may just be intermittent