Review on 🔌 Denso 234-4233 O2 Sensor by Dave Tapia

I bought this as a potentially quick and MUCH cheaper fix to the dreaded P0420 code on a 2003 Toyota Corolla with about 128,000 miles on it. I've heard many differing opinions as to how often replacing this oxygen sensor will actually fix the problem. I figured if I ended up replacing the CAT I'd be replacing the oxygen sensors anyway, so what the heck. Why not try the cheapest part first? I've now driven about 250 miles and checked the condition of the catalytic converter system with my code reader and it actually worked and apparently passed one last time. The light has been on almost continuously for the last year. I'm not overly optimistic as I suspect my cat's system has actually decreased in efficiency, but hopefully that will give me a year or two more. Corolla of the same year and I want to try to get rid of the light I did the following. Around the same time I installed a new oxygen sensor, I changed the spark plugs to NGK IRIDIUM. Shortly thereafter I also drained/added my transmission oil, drained/added coolant, changed the oil to semi-synthetic. I created these three items after being pretty sure the code was fixed, so I don't know if they will affect anything or not. When the lights come back on I'll try to remember to update this review for those of you. who have the same annoying problem and don't want to spend $$$$ on a new factory CAT.