Questions about 02 & Air/fuel sensors

Attached or some pics of my new sensors and old sensors. New ones are from Rockauto. I pulled my front sensor out I suppose it is considered a Air/fuel sensor. But the old Air sensor does not look like the new air sensor. It looks like a 02 sensor. Plus the new Air/Fuel Sensor connector is not the same but the new 02 sensor connector is the same. Truck is a 2000 model could it possible they didn't change from front 02 sensor to Air/Fuel sensor at sometime it was a left over where they have (2) 02 sensors front of the cat and the one behind the cat? Anybody I could use some help here. Thanks

 

the old one doesn't look like the new one because it is OLD. If the plugs are the same, you should be good.

 

Yeah i know its old. But would it matter the old having so many more holes in it versus the air/fuel sensor having fewer holes. Plus why would it be called a air/fuel sensor versus 02 sensor. Is there a difference in the them besides the holes in the sensors?

 

they are the same thing. the O2 sensor reads the amount of gases and helps your ECU send the signal to the fuel injectors for the proper amount.

 

How much did it cost if you dont mind asking, i have to replace mine in my 99 and havnt got around to check what they run....

 

Denso Downstream was $54.79
Denso Upstream was $116.79 I think I need to send back the upstream one because mine is just a regular 02 sensor I guess. instead of a Air/Fuel Sensor plus it will save me about $60 dollars.

 

Look in my picture they are different Air/Fuel Sensor has 8 holes spaced apart around the sensor and one on the end. And the 02 sensor has 18 holes spaced apart around the sensor and none on the end.

 

Thanks!

 

Well finally got it figured out about the A/F sensor. My truck is a non California model meaning it is a Federal emission type even though it was made in California according to my VIN. Doesn't mean it has Calli. Emissions. It also is a lot cheaper for the Non Calli. A/F sensor by about $60. Information somebody else may use in the future. Check under your hood and see if it is Calli. emission or federal emission should have a tag on your hood. Mine didn't. People at Rock Auto or excellent on customer service. They took the time to figure it out. And A/F sensors are different they monitor your fuel better than just a plain old 02 sensor. Kuddos to BamaToy for his help.