Oxygen sensor

Hi,

There are 4 on the vehicle. I am assuming you meant it is a 5.3L. If that isn't correct, let me know.

Now, you have both upstream and down stream. All that means is this. The upstream sensors are before the catalytic converters. The down stream are after it.

It breaks down further. The are identified by Bank 1 and Bank 2. On this vehicle bank one will be on the driver's side and bank 2 is the passenger side of the engine.

I attached a pic below that shows the sensors and how they are located in the exhaust system. Take a look at it and let me know if you have questions or need help.

Take care,
Joe

Hello,

If it has dual exhaust or two catalytic converters it should have four one before and on after each catalytic converter. The ones before are considered upstream and the one after downstream. Take a look under the car by the rear of the engine and you should see the cats. You may not see the sensors just verify if there are one or two catalytic converters on the system. This will tell you the number of sensors. The catalytic converters will look like small mufflers. Most all V8's will have two catalytic converters and four sensors.
Tom

Happy to help. Let me know if you have other questions.

Take care,
Joe