Hi, I need some help finding the front Oxygen sensor. I found and replaced the rear one shown in this video: . Anyway where is the other sensor? I'm not sure if the location varies for different models so I have a 2001 4 door 4 cylinder Alero.

 

look in the exhaust manifold area-must be somewhere upstream of the one u replaced.

 

I actually ended up finding it thanks to the attached diagram

I didn't see it because there is a plate over top of the manifold. I will take pictures to help anyone else out having trouble finding it.