Make sure to pull the banjo bolt from the the rear of the intake and clean it. A line runs from there up to the crossover valve, which should be mounted on the firewall. Clean out that line also. Then check the crossover valve. It may be plugged as well. The crossover has a 12v connection that releases the pressuse in that line. If the crossover valve is plugged, then remove it (just two screws) and rig a 12v line to open the valve and clean it out so that air blows through both open and closed.
The line hooked to it continues from there to the aneroid. That can be a problem too, but first thing is to check to see if air pressure is being passed along that line to the aneroid. It is ofter plugged a long way up the line.
The purpose of this is to send pressure to the aneroid when the turbo is running. The aneroid in turn causes the IP to run more fuel through the injectors. Without this working you get little power with the turbo boost.