97 Jetta loud cat conv/tiny engine stalls

Hey all!
Last year the catalytic converter on a 97 Jetta was replaced because it failed emissions and there is a federal warranty on cat. convs. which says if your car is under 80,000 miles you get a new one for free. So that was done, Now about one year later the cat conv is sounding loud and the car will have tiny stalls here and there. Could the cat conv have went bad again? Is there a different problem? It has trouble especially after stopping at a stop light and beginning to accelerate. THere have been new plug/wires, fuel filter recently put on.
Any help would be awesome!!!!!

Does the check engine light come on?

No the engine light didn't come on, and no codes given off either. VW found the problem, an exhaust pipe leak, it sounded around the area of the CAT. Hey, do you know a good computer code reader for a car?

is the cat loud sputtery sound? or is it a rattle of sorts.. could be broken inside and clogging the pipe????

Ross Tech makes a VW Group dedicated VAG simulator for PC that basically does everthing a dealer can.

http://www.ross-tech.com/

I would also make sure you ignition coil is okay, they were very common to fail. Try spraying it with water & see of those little stalls & acceleration trouble gets worse.

Where did you here that it was federal law to replace cc with under 80k miles. Please let me know where I can find such information.

It's in the warranty section of all owner's manuals