Ok let's clear some stuff up. When you say the boost spikes then drops when is this? A spike should only last like a half second. Or its holding 9psi then starts dropping as you hit higher rpms?
Higher gears put a larger load on the motor, which can cause boost creep, which is what your getting . Toss that wga, sounds like a piece of s***. Get a better one and everything should be fine.
