I would guess the fuel pressure regulator is at fault...but I don't want you to continue to throw parts at the problem...
...do the diagnosis one step at a time...fuel pumps on, fuel relay operational, fuel injectors and seals okay, etc. etc.
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car