I'm adding to my initial post. Truck won't start (cranks fine) no DTC's no air in fuel. have'nt checked rail pressure (my scanner won't). I have approx. 150 ml of fuel return cranking. Is it possible pres. relief valve is stuck or fuel pres. regulator is causing this problem? It started fine over the weekend but I had to use the priming pump the first time Sat. and again on Sun. then it was fine. Shut it down Sun. afternoon would not start on Mon. I messed with a bunch of stuff and it started yesterday, ran good,restarted immediately after shutdown but would not start again this am. I checked fuel return rate and it was about 150ml while cranking (15 sec.) If the pressure reg sticks would I get a high return rate?