My truck has a problem the dealer is attempting to solve: Lack of power at high speed and poor mileage (<22 mpg) at highway speeds. Field rep agrees there is a problem but they haven't been able to identify problem yet. One item I've noted is the truck is downshifting a lot on small grades which it never has done before. They are not going to start throwing parts at it now. First on the list is a new turbo and EGR. Hopefully they are installed this week. I was hoping that someone has an idea on potential root cause/s. The dealer has had my truck for the best part of 2 months. They have provided a courtesy car though. Truck has 80K on it. i love the truck ...but it has a problem...............