My experience with the new 6.7's is to bring it to the shop. It's a dead duck and it will only get worse. They do have a new flash (July) that seemed to do the trick. Can't say how long it would last because I dumped the truck through the lemon law before I got a chance to put any serious miles on it. Oh, and the new flash cut my mpg in half (weren't very good anyway)
Dealer is going to tell him it's his fault for not running it hard enough (comes from the dodge dealer 6.7 playbook).
Good luck to your friend. I personally have been through numerous turbos, dpf's, egr's, new cat converter.
Some have had nothing but good luck and some have had dogs!!!
