Hi all, I have an 02 z track car with no emissions and headers cam etc. oem fuel system.

What happens is the car seems to pull power back at full throttle.
Idles fine and ok at mid throttle but not full throttle.
When I blip throttle the fuel psi drops a few psi. I think that’s normal.

My fuel pressure readings seem low according to the shop manual, should be at 55-62 psi with ignition on only but reads 36 psi ignition only and 45 psi engine running. After I shut engine off psi climbs to 60psi. Is this normal to climb to 60?
and could I have another fuel filter/regulator that’s low psi or bad? I’ve heard the quality control can be suspect on some of these fuel filters/reg.
I initially bought a gm replacement and now I have a tanks regulator/filter installed.

I did replace oem fuel pump and I’m on my second fuel pressure filter/regulator.
Any insight would be great! Thanks Brian

 

Sorry I missed this post earlier. So you are saying that with the engine off and key off the pressure climbs to 60 psi? Since the fuel pump is able to provide 60 PSI then that would lead me to suspect the regulator, even though it's been replaced once it sounded like from what you said that it was not a GM part but aftermarket.