[ricksza]

The programming update was to cycle the EGR valve during decel to break up the carbon chunks. Do you have the computer under the dash or on the RF wheel well? There is a bulletin for replacing the PROM in the under dash computer for this concern. I'm sure that the is a programming update for the other one also.
It's possible that at the dealer, that during checking he commanded the EGR full open and the carbon dropped out (can do that with the factory scanner). With the scanner, they can check if you have the latest program for your vehicle, or you can remove and clean the EGR valve yourself.