i know there's two oxygen sensors, the upper and lower

1997 CHEVROLET MONTE CARLO

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It has the 3.4. And i know there's two oxygen sensors, the upper and lower. I can find the lower behind the converter, but where is the upper located? I know it's in front of the catalytic converter somewhere, but where???

Mar 6, 2010 at 3:02 PM

SQM

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Hello,

There are two upstream (upper) oxygen sensors. One in each exhaust manifold. They could be little difficult to see due to several components that can block the view.

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Images (Click to enlarge)

Oct 28, 2021 at 9:43 PM