catalic converter-if light is on you may need a new cat converter.

First off, sorry, could be a bummer of a problem to fix.  I recommend checking out Autozone to see if they have a code reader for your OBD-1 Mazda.  It may work with a Ford code reader.  If not, I would try to find a website with Diagnostic instructions, typically there is a Diagnostic Port that you can use to check codes.  The catalytic converter is an emissions piece located in your exhaust, looks somewhat like a small muffler, and is  usually just downstream of the engine.  That is the piece that most likely needs replacement.  Good luck.