Someone suggested fuel pump, but I definitely have fuel and plenty at WOT. 48 psi at idle (as it should be). I read in the other thread the fuel pressure regulator can go bad, but I am pretty sure mine is good, as the pressure readings are as they should be, and when the hose is removed it hisses and the pressure goes up to what it's maximum is I believe.
It doesn't leak fuel as far as I can tell, but if it did it a bad FPR would explain poor fuel economy, running rough and such. I just moved the fuel pressure regulator to the new fuel rail last week, first time it's been removed and then reinstalled.
Eh, nah, I've been reading around:
Quote:
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With the engine running, disconnect the vacuum hose from the pressure regulator. As a rule, fuel system pressure should increase 8 to 12 psi with the line disconnected. No change would indicate a faulty pressure regulator.
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It does this. Holds pressure fine, regulates fine, I never run out of fuel.
A misfire would explain everything though so I'm hoping the boots/springs/coil pack housing/plugs fix it. If it's misfiring then the upstream O2 would remain on the rich side more often than before. The graph is jaggy but there's more little jaggies on the higher (richer) side of things when monitoring the upstream O2.