fuel pressure

[dev024]

Hey guys I think, my fuel pump is giving up. Could somebody please tell me how to check the fuel pressure, the fuel regulator? I couldn’t find a fuel valve on the engine. And what are the symptoms for the pump when is giving up? Please advice on what to do. Thanks in advance

Ok the car is a 1993 Nissan 300zx N/A. with 80k. a week around 3pm I was driving with great weather condition was around 70 degrees which is not bad for San Antonio haha. As soon I got on the freeway I step on the gas to reach the speed limit which is 70 but around 3000 and 4000 RPMs my car felt like it was not absorbing gas. My foot was still on the gas pedal, but the car loose power completely, (the way this felt it was like somebody was trying to pull me) this is the like the fourth time it happens to me. After that I decided to return home, the car was stalling at every light and stop sign, it even turn off on me two times. Usually it happens when the car is cold, (when is cold since winter started, I turn it on, and after a few minutes the car will stall on me and then turn off, sometimes not always there is a little whistling sound coming from the back (trunk) this whistle sound I have been hearing for the past four months when I am hitting the gas only.) this is the reason I suspect the fuel pump is bad, . Now besides that the car feel strong .
one of my friends told me that the car may not be getting enough air, which to me is weird because I just replace the stock air box for an aftermarket k&n and at the same time I took my time to clean the Mass air flow

[BigTDogg (MA)]

Pump will usually make noise before it dies.

You can install a FP gauge after the fuel filter and run it on a dyno to check pressure.

[dev024]

ok ill try the FP gauge , but any suggestion on what could it be?

[BigTDogg (MA)]

pump, pump controller, clogged filter

[dev024]

Ok I did the fuel pressure test. When I turn on the ignition it the first time it went all the way to 48 psi, the second time it went to 50psi, the third time it went 48 psi. After that I decide to turn on the car it stayed on 42 psi just idling, turn it off and did it again and the way the gauge was moving was from 37 to 42 psi rapidly. I turn it off and tried it one more time and did the same thing as the second time was moving rapidly from 37 to 42. I step on the gas up to 2500 3000 RPM’s and the gauge stay steady at 42 psi. I also had the inconvenience that the car shut off, because of the failure I been having and the way the car turn off was: in the moment it was shutting off the gauge move all the way to 50 psi and then turn off at 45 psi., the second time it shut off the car turn off at 50 psi and then when all the way to 42 psi. Now could the pump be bad, or the fuel pressure is bad, because one of my friends told me that for being and old pump is not bad and is working properly. Any suggestion?
Thanks