99 Acura TL Catalytic Converter
Had same problem with my 99tl, problem started when it had 80k but was in warranty for time, called dealer asked if there was a service bulletin, later found out TSB 03-027 was active and state to replaced the cat if you got a P0420, it further said if the vehicle was out of warrranty to apply to the zone for consideration. The acura dealer scewed me around for 2 months and then gave me the 1-800 number, end of relationship with them. Went to my local honda dealer, had a bunch of other 100K work done, had them replace the cat on my dime wrote a letter to Acrua, they eventually paid me for the cat, I paid the labor. It broke down to 865.82 for cat, 10.67 for a gasket, $57 for labor, might want to try a honda dealer.