all of a sudden my car threw a code of p0420 Catalyst System Efficiency Below Threshold (Bank 1) and two codes for an o2 sensor. I checked for exhaust leaks, none. Im not sure if the catalyst could be clogged? it drives fine but when u try to mush on the gas it bogs but when stepping on the gas pedal lightly it will drive normal? Whats the deal? Btw: there is a little smell coming out, i remember that smell when i put the new cat in a few months ago.