Front O2 sensor fault

[Rockford]

Misifirng when cold and lower than usual fuel economy, emissions light on constantly. RStuner states Front 02 sensor faulty, I've searched the forum for a while and few posts suggest this is in the top of the inlet plunum while other says its just before the cat.

I want to take it out and clean it and see if this help, where abouts is it?

Thanks

 

[durham4416]

just replaced mine, lay under the car and there is one in front the cat and one just after the cat, replace the one in front the cat (upstream)