I just want to know if the way the fuel pressure changes is normal. With the vacuum hose on the fpr its at 40psi and 50psi with the hose off. On idle with the hose on its steady at 40psi but when I rev it some it jumps to 50psi. Is that what its supposed to do when you rev it? I thought the pressure should be constant idling or not!

 

Yes, on that type of fuel pressure regulator it's normal, that's how they work because it takes a signal from the intake manifold. When is at idle it sees a vacuum signal and when you step on the gas WOT it sees cero vacuum (atmospheric pressure). There are other types of FPR that don't use a signal from the intake manifold and they keep the same pressure.