when car is cold, it pings, but now its louder. gets better and almost stops on 2005 Nissan Murano

after it gets driven for about 6 min. my check engine light came on and auto zone says its cat converter. i don't have the $ to fix now, will it harm my engine to keep on driving for awhile?

Asked by for the 2005 Nissan Murano
rec. fuel system clean. ethanol treatment to 1 tank premium fuel. ethanol blend fuel causes build up in fuel system, combustion chambers, exhaust system and causes increased wear to spark plugs. build up can cause ping.
rec. oil stabilizer treatment on next oil change. recondition seals and cylinders.
hope remedy helps.