One little air leak will shut any modern diesel down , thats a given. as far as running, they are pretty good engines. I got to drive some when they first came out, I embarressed myself first day driving for a steel yard that had them in their trucks. Was pulling a 40 ft flat loaded down HEAVY with steel through the mountains all day and the fuel gage didnt barely move all day there was only one 75 gal tank on the truck, When I got back to town,instead of heading for the pumps, i pulled into the shop to report a busted fuel gauge ( I have visually checked the tank before leaving and it had been topped off ) They just laughed ( I wasnt the first ) those things get insane fuel mileage , We were getting somewhere arounf 18-20 mpg with those rigs, that was mind boggling considering my pickup only gets that running empty