Fuel Pressure question

[Jsmooth65]

So I've been having some issues on hot days this summer where the car loses all power (flooring it doesn't move RPM), stumbles and stalls out, won't start. I'm trying to figure out what the issue is, since its not throwing any codes besides some intermittent EGT codes. I've got an 044 pump, that sounds like hell (more than usual) on hot days like when this issue happens. I also have a fuel pressure gauge in-line in the engine bay, and when I finally get the car started again, the pressure gauge bounces around instead of holding steady, while idling. Is this normal or is my 044 pump going bad?

[zadeluca]

well as far as i know the fuel pressure will adjust based on vacuum, so how does your vacuum gauge look? is that bouncing around too?

[Jsmooth65]

No, the vacuum isn't bouncing like the fuel pressure.

[zadeluca]

what is the fuel pressure at idle, or what does it bounce between?

disconnect the vacuum source to the FPR and plug the hose, what is the fuel pressure at idle now?