After filling up at a no-name gas station at a nearby Casino, I noticed my SES light came on. After scanning got a 420 (Bad Cat bank 1). I deleted the code just in case it was a fluke.

The next day my SES came back so I scanned again to verify the same problem and got the 420 again. I erased the code again figuring I now needed to get new cats.

However after erasing the code the second time I filled up at my usual gas station on the way home and since then (4 days ago) the SES light has not returned.

Was this caused by bad gas??

 

Did you have th problem since??