Hello all, I know I usually ask some bogus questions here but I really do need some assistance. My Acadia has been throwing P0430 and P0420 codes for a while now and I don’t know what the problem is. I replaced the Catalytic Converters between the engine and the firewall along with the one between the engine and the radiator in October of 2021 and replaced the upstream O2 sensors when I changed them out. I had change out the downstream sensors maybe a couple months before then. I also replaced the Y-pipe with all of this as well. I just recently replaced the downstream sensors because I thought the problem was coming from those but the codes are still coming back. Should I replace the upstream sensors too and hope that my problem goes away or do I replace the converters again period? I meant to add that the codes started throwing probably around spring of 2022, maybe over the summer, I don’t remember exactly when but they started a couple months after replacing the majority of the exhaust. I should also probably add that I have had the exhaust unbolted at the end of the y-pipe, going towards the muffler, I’ve done it a couple times because I’m an idiot who thinks it sounds good without thinking about the repercussions. I never had it unbolted for more than a few days though before putting it back together and snugging everything up and leaving it for a while. Could my stupid actions be the cause of my problems? Could it be something else? I really need help because my tags expire next month and I’m pretty sure I’m due for emissions this year since my car is an ‘09.