Fuel regulator on l200

So I set up a fuel regulator on the l200 how another member said to do it.
It fixed the problem of pushing fuel back out of the injectors when on boost.
But it runs shit when cold and uses a lot more fuel.
Is this because it’s not set up correctly or the injectors can’t handle the pressure increase

Do you know what pressure it is set on? What pressure reading do you get when you remove the vacuum line? I had an AFR wideband gauge and with std ecu I’d set the fuel pressure so at wide open throttle it’d be 13:1

You might need a rising rate FPR

Think the gauge was reading 45psi.
Any less ant it doesn’t want to idle. It won’t go past 50.
When warm it’s fine but fuel use is high

45psi may not be wrong. Do you have a vacuum reference line? Hard to know what is the right pressure without knowing the afr.