cat catalytic converter

I had a new catalytic converter installed now my o2 sensor light came on why now not before installation

ZZP 2013-2017 Buick Regal High Flow cat. Replaces factory cat at the turbo. Contains 400 cell cat. Installed for 2 days and 50 miles before being removed. Comes with mounting bolts, turbo gasket and Megan Racing 02 spacer/ adapter. The adapter is supposed to remove the check engine light...

I have a 2015 Buick Encore that has had a catalyst converter replacement by the used dealer which I believe is a generic one by the invoice price receipt. is that OK for my vehicle? or does my vehicle require the name brand catalyst converter and order to run properly? The GM dealership said...

2002 Park Avenue Base model 3800 So, I have a clogged converter. I had the sluggishness, the jerking, etc... Changed all the usual suspects to eliminate the problem and tested all the sensors in an effort to avoid accepting that was the CAT. It wasn't until exhaust coming through the EGR into...