Diagnostic Trouble codes P0420 & P0430 are only thrown when your cat's are blown out.
It's probably time for a good tune up.
1) New Air/fuel filters.
2) New plugs
3) Clean the MAF & IACT sensors with CRC MAF sensor cleaner.
4) Clean throttle body.
5) New upstream H02 sensors.
See
http://www.catalyticconverterwarehouse.com , for new OEM cats.