Wondering if there's a way to review the history of computer trouble codes.

The main thing in what you have written is that the cat converter(s) are suspect...these are not cheap, even if bought aftermarket. Several hundred dollars minimum. On an older car, that can really sting if you paid full used car price for it, and then have to drop the better (or worse, depending on how you look at it) part of a grand on a repair just to get it inspected. I would insist on the dealer/owner getting a new inspection at either a state site or a shop of your choosing, depending on how your state operates. Anything else could lead to you crying the blues on this site in a few days or weeks.

I did not post the original question here!.. Is this an answer or a reply??