2005 GMC Envoy..recent problems include engine light, brought it to the VIP and read code for cam shaft sensor, went to the dealer and had it replaced! The next day it staled while I was driving 45 mph, had to coast to a stop and park to restart, has happened four more times, dealer now said it is showing three more codes. Excellerator, instratrument cluster and wire fuel pump controler??? what is going on here..any ideas??