My truck is a 2012 6.7 L with 70,000 miles. Over the last couple of years I have experienced brief periods (several minutes max) where my power would decrease significantly and then return to normal within a minute or two. This issue is happening with no cargo or towing load. This morning (2/6/2017) on the way home from work (50 mile journey) I experienced significant power loss almost the entire way home. Tonight returning to work the power felt almost normal as I merged onto the highway. Approximately 35 miles later the truck suddenly lost power and could barely maintain 75 MPH on flat ground. In order to maintain speed crossing overpasses I would have to push the accelerator to the floor and downshift to 5th gear. Fuel filter was replaced at 60,000 miles so I don't expect it to be plugging. Engine is not running rough and obviously the TPS is responding as the throttle position is properly downshifting the transmission. RPM's do not indicate any transmission slippage. This is an intermittent issue which is making it very difficult to trouble shoot. My best guess is that something is cutting my fuel supply pressure or flow and all of the obvious mechanical parts of the system seem to be OK. Any ideas / suggestions??
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