Ok need help, got a 3ZJ manual pump 3406 cat. When I first bought Truck (Oct 2017) it would pull about 15 # manifold pressure and no smoke. After driving around 30 days, one day while coming home empty it all of a sudden started pulling 21-22# and trailing a little smoke. Had more power of course so I continued to watch the pyro and nothing over 750 so I continued driving it that way. Skip ahead to last week(Feb 2018), loaded headed west it all of sudden reverted back to only pulling 15# mp and trailing smoke stopped and felt gutless. Came home changed filters replaced transfer pump, checked fuel pressure (45-50+). AFRV plunger was removed to eliminate that, still doing same thing. Can start off leaving driveway and drive 5+ Miles and it’s 21-22# then all of sudden while still pushing accelerator it falls off to 15# and seems to flatline. It has blew my mind why it would go back and forth doing this. Any tips???