Go to an autozone, pep boys, whatever and buy a code scanner. They are cheap now and there is no excuse in not having good information. If you have time order this: http://www.amazon.com/ieGeekŪ-Wirele.../dp/B00B3K2X4M

points on the name...

When you get the codes look them up and read about what is happening under the hood. Here is an article that explains a little more about catalytic converters.
The Misleading Nature of the PO42O Code - Eastern Manufacturing