This engine was in a shop that replaced several things including all the injectors on the 2-4-6-8 side. New oil cooler and egr and low wiring. Engine ran great for a few days then got P0284. They found that the lower fuel filter had gunk and replaced. The engine ran fine for a few days and then P0284. I put a pressure gage on top filter lid and the pressure is 56psi idling and running down the road. My plan is to pull the lower filter and check for gunk and replace. Run and see what happens. Next I plan to pump fuel out of tank....and rinse it with something. Question: Am I on the right track?