Brief info: I ran 12.6@109mph with 323hp.. then I decided to rebuild the stock bottom end, planning on upgrading turbo and injectors next...

New mods: JE Pistons, Crower Rods, ACL bearing, OEM oil pump, ARP main and head studs, cometic gasket, cams springs and retainers...

Existing mods: AMS intercooler, injen pipes, act clutch, 10.5 hotside turbo, o2 and downpipe, 3in exhaust, Eboost2 BC...

After the rebuild I dynoed the car, 349hp@21psi... AFR was between 11.1-11.3 in my aem analog wideband and the lm1 of the dyno.... car was running great...

The problem: Last week I did a 3rd gear pull and AFR was on 13's, other day after work did another one, AFR was on low 11's, yesterday AFR was on 13's again , I bought and installed today an Aeromotive 340 replacing the existing walbro 255... decided to do a cruise, I connected an multimeter to the fuel pump connector, car cruising its getting 7-8 volts, at 40%+ throttle only gets 11.6volts and the AFR its lean...
STFT its crazy, don't know if its by the low voltage on the pump or a faulty O2 sensor. I have a CEL on, of a O2 and p0243 because last owner remove the solenoid

ROM ID: 94170008

I attach the evoscan log, rename .zip to .csv.