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

1997 CHEVROLET MONTE CARLO

WONTFALLSHORT

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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

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SQM

CAR REPAIR CONTRIBUTOR
6,383 POSTS

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