my fuel rail pressure will drop down around 1-7 psi, i already changed the frp sensor. so im lookin at the maf now, when i did the logging it threw up 2 codes and so i took it to the ford dealership and the guy told me that it was either maf or bank 2 rear o2, but the first data logging i did several months ago showed all 4 o2's runnin up to 4 volts. but ive been told that the o2's have no effect on it at wot. so any ideas. fuel filter is new.