What would cause this, i am working on this car for someone else, i know there are a handful of wiring that is not done the best way but overall it is running fine the first time it ran fine and got to 10 psi, the second test drive every time it got just past 0 psi on the gauge it would hit overboost cutout.

What would cause this, i have the purge and wastegate solenoid codes but looking into the 87 LM code that shouldn't cause this problem.