I finished installing my Autometer 3313 mechanical fuel pressure gauge last night and am somewhat concerned about the pressure readings. From what I have read from you all, normal pressures are about 15 psi at idle and 8 at WOT. I am getting 13-14 psi at idel and 3-4 psi WOT. I replaced the lift pump three days ago, so I'm pretty sure that's not the problem. I'm thinking that maybe the reason for my numbers is that my gauge is mounted on the pillar, which is about 2 feet higher than the isolator.