What is oxygen sensor for?

Can someone tell me what is the purpose of O2 sensor and how it helps the car?

Air/ fuel ratios for the car. OBD II vehicles are equipt with 2 of them, primary in the header and 1 after the cat.

mine only has one!! work that out!!

a/f as Cody said, you'd be surprised how much it can mess with the fuelling if it's fukt. i had a brand new bosch mess me around and then problem solved when I put the old AC Delco one back in. NTK or Delco form now on

mine only has one!! work that out!!



Possibly an O2 Simulator?

^ nope just one o2 sensor. as it was, as it is!

those sims don't work right though

mine only has one!! work that out!!
Is your car a 95?

No, his is a 1997 Chevrolet Z24.

^ nope just one o2 sensor. as it was, as it is!

hmm... must be something dealing with your car is canadian then. Other wise you got me...

i don't know why either to be honest. 97 2.4. could be a canadian thing as there doesn't evn seem to be a wire/connector for it. and i replaced the motor myself so I would have noticed!

thats different