I was wondering how critical they are to the performance of the engine? I know what they do and how they do it, but I was wondering if they get less sensitive with age??? My car seems like its running rich lately, and it has a good tune up on it......any info would be great. Also, is it hard to change the 02 sensor if you have the special socket for it???? Thanks in advance

 

Yes, the O2 sensor can go bad with age. Things like lead in the gas will poison it. Cleaners containing chlorine or fluorine, when burned, release the chlorine which then corrodes the sensor. If you have a lot of carbon coming from a cylinder, that can coat the sensor. If you've used a silicone sealant or gasket compound, or silicone oil, it's possible for silicone vapors to get into the engine. After burning the silicone poisons the sensor also. I've heard it's not hard to change the O2 sensor, especially with the special socket.