Intermittent problem - code 16804

[CathyDad]

I have started setting a DTC of 16804 (P0424) "catalyst system bank 1 efficiency below threshold" on my 2002 new beetle 1.8 turbo. It seems to jump in when I get a bit heavy footed on the pedal. Could it be a bit too much "Fahrvergnügen"?
No other driving problems and the car has performed pretty flawlessly since I cleaned/inspected grounds, etc when doing the airbag controller replacement last summer.
I have read that the problem may be cat converter failure or impending failure - something that decreases efficiency, but I have no idea what "bank 1" refers to or what the threshold may be. The manuals are not much help with suggesting repairs, only describing the code.
Any help will be appreciated.
What is the warranty on the cat? 8yrs/80,000? How much resistance from dealers on making repairs?? I am getting very close on mileage.

[CathyDad]

Still no idea what may have caused the codes to set, but have not had the problem since I posted the problem. May have also been some issues with the particular tankload of fuel. No ideas, but should this come back, I will revisit the forum.

[CathyDad]

Just me again--

Ends up that the catalytic converter did require replacement after all. It started setting the code more often so with less than 200 miles to go on the emissions warranty, I dropped it of at the dealer and they did the repair under the warranty - then hand washed and vacuumed the car spotless.

What a great service - even after Christmas.