1995 850 Turbo-Great Boost after relearn, then not so great

[gordo850turbo]

For the last 3 or 4 times we unhooked the battery to work on car, after we went through the relearn sequence the car runs great with max. boost when you floor it. But after we shut it off and then the next time start driving it normal, it will only go to about 1/3 boost when you floor it. Otherwise it runs fine. Checked codes and only got a A3-141 code for the brake position sensor. Would that be effecting the boost? I have read where newer cars go into a "limp" mode with a bad BPS. Could the computer be limiting the boost because of the brake position sensor problem? I have replaced most of the vacuum lines under the hood and rebuilt the turbo. My son wants to adjust the waste gate, but I don't think that is the problem since it works fine one time and then doesn't work later. Any suggestions?

[abscate]

The ECU on later cars definitely limits boost under certain faults, and a vacuum leak is certainly something that will catch its attention.