2011 Equinox 2.4l. Just had the rings and pistons replaced courtesy of GM.
My downstream o2 sensor used to run at .8 volts and was very steady. Now it looks like this. Yes car was warmed up.
Catalytic converter is still under warranty and in fact GM extend the warranty out.
No codes so I'm guessing that it's starting to go but not bad enough yet for a code.
Or maybe everything is fine???