Originally posted by ChadEbert:

From what I understand, once the CEL comes on, it has to be reset to be turned off



No.




Engine?
Mileage?

It is likely that your CAT is starting to go south.
Fluxuations in mixture durring specific drive cycles is causing the CEL. If you can fix the source of those fluxuations the light will stay out - for a while.

"Those who cannot remember the past are condemned to repeat it" -George Santayana