E5 GSR,normal stock one but 2.5 inch exhaust systerm and intake pipes.

my problem is fuel cut when spool just @ 0.5bar and running too lean .idle 14.7 ,as rev ups the A/F ratio shows 14.7 to 18.x the fuel cut comes.

Today I changed my pump but still running lean .when wot it fuel cut @ 0.5bar. I was thinking about it may be caused by the fuel filter in the engine bay.

A funny thing that I checked the pressure from fuel pump is 2.5(just within spec) but its "0"bar at the return line in the engine bay.I just disconnected the metal fuel return pipe with the rubber hose where the FPR fitted there's even no fuel out when idle!!!

some say its more than 2.5 the fuel rail pressure actuator begin to release pressure ,so the FPR gauge shows "0"?is that true?

I can make sure the pump,the injector resistor, fuel pump resistor,FPR ,MAF all of above is ok.I checked the ohm they are all fine within spec.

it seems like somewhere fuel pressure leaks
I think maybe I should check fuel rail pressure actuator and injector and fuel filter tomorrow
.Is there anything I should take care?
Any help and suggetion will be appreciated !
thanks
Jimmy