My cel came on on the way to work yesterday. Got a code 0702 (front catalyst right bank). I've had my ws y-pipe on for about 6 months & 4000 miles. I just reset and it didn't come on today yet. Anyone have a problem like this? I did install new O2 sensors with the y-pipe, but O2 failure is a different code right?

 

It could, if you've got an exhaust leak above the upstream O2s. But after the mileage you've put on it? Not likely.

More than likely though, the rear O2 sensor just died, or your converter is indeed bad.

Have you tested the O2 yet?

 

I replaced the cat at the same time as y-pipe, replaced the rear O2 maybe three years ago. If my cel comes on again, I'll check as you suggest.
Thanks!