Yes Mike I have the same code P0420 once in a while will also read P1153.
when I first purchased the vehicle 2008 chevy with 5.3 would get a CE light about once every 2 or 3 months now it comes on every week or 2. I purchased a Blue reader still can't figure out what the data means or the issues they don't seem to help me at all. I replaced all plugs and wires about a year ago and had a shop install 4 new Denso O2 sensors. No change. Lately light is coming on more frequently. Every time I come to a light I cringe waiting for the idle to change a bit then light to come on. Only issue is a slight roughness to idle once in a while. I took to Midas they said Cats are good and nothing wrong with vehicle. I have no rotten egg smell and they did an intake injection cleaner for the tune of $ 450.00 (robbery which I could have probably done myself). light came on about a week later. these computer vehicles are the pits.
