well, first off.

rule out the Boost Bypass Solenoid as the reason for 1/2 boost.

disconnect the boost/vac line on the BBV (bottom) and plug the line that was feeding it so you don't introduce a vac leak.

and unplug the harness... your BBV should stay constantly closed now.

see if that affects your boost.. if so you might have a poopy BBV or wiring issue.