So, the next morning after purchasing the car the night before, the check engine soon light comes on...

Today I brought it to autozone and they did the reading...

Comes up as a problem with the CAT in bank 1....

I was told it means I need a new CAT on the left side??

Please help...

Thanks as always!

Our cars only have one cat. Therefore it would potentially be a bad cat. Having a parts store scanning the code is good. However their diagnosis can be incorrect on many things.

Did you happen to get the number of the code? If not, I'd probably suggest letting it appear again, have it read again and getting the number. That way you can be sure you need a new cat and not something cheaper and simpler.

Hmm, bank1, wouldn't bank2 be a bad cat? I guess I really need to look this car over. Get up here Saturday if you can, I'll fit you in best I can.

The rear O2 sensor monitors the cat.

Im guessing this is why my 2000 sle is now with SES after I cut out the cats the mufflers and replaced them with pipes?

Well it seems after giving the car a good run on the highway (100 miles) this past Saturday, the check engine light went off...

I have also gotten the "Check Fuel Cap" notification twice now, but just hit the reset button and it goes away (I checked the fuel cap).