P0420, P0430 are EGR efficiency below threashold, banks 1, 2.
Chances are a good TB cleaning will take care of this. About 2 hours of EASY work, a $3 can of Berrymans B-12 chemtool spray from Wally-World, and a TB gasket from the dealer should get you squared away. Check out how to do a good TB cleaning - Should look like this:
TB cleaning If you must have it done for you, any mechanic or CEGer in your area will be able to handle it for under $100. Just be sure to show them the picture from above & they know to clean up the passages behind the TB gasket.
You might want to change the O2 sensor, too; as that's what the guy at Auto Zone told me to do.