Review on Upstream Air Fuel Ratio Oxygen O2 Sensor 234-9051 for IS250 GS300 GS350 IS350 4Runner FJ Cruiser Land Cruiser Sequoia Tundra Tacoma by Keith Aluguvelli

They didn't last last. The descent took 6 months at most, the ascent took less than a year. The codes seem to be too lean or too bold, I think it can't be the O2 sensor, I just replaced them and the codes are bank dependent too so you know it was that article. Asked the seller about the downstream warranty, said he would give me $11 or anything said no, I want a new one, I haven't installed it for 6 months and now it's bad. So sent confirmation of the codes etc and fixed the problem then it went away again so paid for denzo and no problem then got codes again so checked everything else it might have and ended up with updraft sensor a better brand again bought which is not as expensive as upstream denzo because they are more expensive and the problem is not fixed so just do it right from the start, i didn't realize how important the quality of the o2 sensors is and i am very wrong , I went denzo 12 years before the code or problem with the original and they lasted less than a year