96 lumina o2 sensor

[zanatose]

I need to know were the o2 sensor's are after my catalyitic converter and how to check them to see if they are working please.

[maxwedge]

Welcome to AF, there is one sensor just after the rear exh. manifold and one right behind the cat, this one does not affect performance, a scan or a graphing scanner is required to check if they are operating normally, usually if not they would set a code.