Problem With Fuel System(Maybe Not?..)

[RB_Brother]

Hi everybody! I decided to look for help here, because in Russia, I have no one can help. Rather, those who know more than me, do not share information.

I am a Skyline ECR33 owner. It have RB25DET, GT35R on top mount, Denso 550cc injectors, Apexi PFC L-jetro with boost kit, stock purple MAF, Tomei Camshafts 256/8,5, AEM Wathermethanol system, Bosch 984 fuel pump.

I have a big problem with A/F Ratio. In 2013, she was, but was manifested not so serious. The boost was 1,2-1,9 and A/F Ration is lean from 10,8 to 11,2-11,3. But after replacing the camshafts it was showed much stronger. At 1 bar it lean from 11,1(in fuel maps) to 12,1 on 5000 rpms, & to 6500 rpms it was 13,5.

Replacement of the fuel pump did not help(new fuel pump - AEM 320 l/h). A/F ratio is lean much stronger...

Now I put Bosch 984 in the fuel tank, & Walbro 255 l/h under hood... A/F ratio is more stably than before, but sometimes it problem manifests itself again slightly weaker...

My friends assumed that it was because of stock purple MAF. At 3400rpms when boost is peak, MAF voltage is 5,12 volts, load increases and the data has wasted no air... Could it be that?

Voltage at fuel pumps - 13,7 at all time, ground is connected directly. At 4,2 bar in fuel rail it was 300 l/h...

I was very tired already this fight ... I do not know what to do.