What's your idle speed running at? Is your speedometer working fine. Does your automatic suspension work properly.
The system that controls the variable steering assist uses inputs from the throttle position, steering rate sensor, and ABS sensors to determine proper boost levels to allow.
One thing I forgot in the PM I sent you, I think the EVO valve is a fail safe valve, thus if it is disconnected, it will fail open all the way allowing full assist, rather than failing closed, or partially closed. So you might try just disconnecting the harness off the valve at the P/S pump to see if you get high boost always. If so, then the Pump and lines are probably fine, and the problem is either in the valve or in the inputs to the control system.