Hope you are all having a great 4th of July weekend. I bought a KAX o2 sensor set of 4 from Amazon. My currents sensors are bad(shock). The instructions do not indicate which is upstream or downstream. The sensors part # is KX2SO20750 and KX2SO20740. I did a search in the forums and the internet and did not find any information regarding these sensor.Thank you very much in advance.

 

Return them and buy either Bosch or NTK off Rockauto.

 

Or Walker.

 

Agree, return and I second going with Walker or NTK. I went with Walker because they were less expensive and got great reviews on the forums. I replaced all four and my O2 codes disappeared.