I have a 2008 with 6.4l with about 80,000 miles. A few days ago, it suddenly lost power while driving on highway. I had it towed home. It continues to start and idle roughly, but will not rev up. The only code is a P0670, which is a glow plug malfunction code. I changed the fuel filters, but there was no change in problems. All stock, no mods.
Was there any noise associated with the sudden loss of power? Did your boost gauge show a no-boost situation? Check that the hose connections on all your boost tubes, especially the bottom of the intercooler (driver side), is on and tight.