Rb25det rich under boost

[yanay]

Anyone know what could cause 9.9 a/f ratio during boost? Good air to fuels in all other aspects (idles 14.2-15.1) Crusing is 12.6-13.0. WOT suddenly drops afr down to the 9s and i lose all power. Im driving the car 400 kms tomorrow morning with no option of not taking it and would really like to get it figured out by then thanks in advance.

Rb25det s2
Precision 5252e 10 psi
Front feed intake
External wastegate
No bov
Walbro 255
Stock ecu

[Skym]

A 255 lph fuel pump can make it drop into 10's at mid to high rpm (where injectors are open more), as factory fuelpump is only 135 lph. Combine that with switching to knock fuel map it might run into 9's. But on knock maps engine should struggle to accelerate or not accelerate due to ignition timing being pulled to 0 on knock ignition map.

[yanay]

It doesn't feel like it's accelerating, it seems 2nd gear is the worst for it. normally it spins all the way through second if it's wot now it doesn't even chirp the tires hitting 2nd on WOT