even if fuel pressure is good, can the flow be inadequate?

[Ruffian]

You may need to look into your afm. at wot/high rpm, your armature may be sending a false reading. Look for an article on how to adjust the path.

[Special_K]

FPR is new

[Rolla1990]

Try driving it with that vacuum line pinched off or disconnected. Your FPR might be junk.

[Special_K]

Yes, but not significantly.

How much is significantly? I remember at idle it was around 42 psi. Medium throttle caused it to dip well into the thirties iirc.

When disconnected from vacuum, the pressure shot up to something like 55 psi (and the motor actually idled better).

[bejbis]

a dumb question, but are you positive your FPR is hooked up to a vacuum source?

[kronus]

EDIT for noob question: should the fuel pressure decrease when i rev the engine?

Yes, but not significantly.

[Special_K]

fuel filter is 3 weeks old.

In terms of injectors; A plug got fouled a few months ago from some crap that was sucked up in the bottom of the fuel tank. maybe the injector has some of that crap still in it.
Clean the injectors with brake parts cleaner? (the stuff i found in the tank was most susceptible to brake parts cleaner and paint thinner [methanol & toluene i assume])

One other little thing i just remembered. Oil leaks from the return tube from the intake manifold to the oil pan. Not badly, but just enough to piss me off. Maybe there's a vacuum leak there as well?

EDIT for noob question: should the fuel pressure decrease when i rev the engine?

[u3b3rg33k]

Your injectors could be dirty and not flowing enough into the actual motor, regardless of the fuel pressure.

I think this is most likely.

Can the fuel pump shoot the correct pressure at idle, but not the correct flow under high demand?

Yes, but I doubt it's the problem. if you have the original fuel filter, it might be time to change it.

Easy way to tell is to tape the fuel pressure gauge to the windshield, and go for a drive.

[kronus]

Your injectors could be dirty and not flowing enough into the actual motor, regardless of the fuel pressure.

[Special_K]

When i get up in the high rpms (5k+) under high throttle the car sputters and loses all power. The check engine light immediately comes on. Stomp test throws a lambda code, indicating a lean out.

Alternately, i can ease it up there with very little throttle (aka less air)

So i borrowed the autozone fuel kit. The fuel pressure is fine along with the regulator.

I would say vacuum leak otherwise, but we sprayed starter fluid all over the vacuum side of things and fixed every leak we could find.

Can the fuel pump shoot the correct pressure at idle, but not the correct flow under high demand?