Just don't lift.

But really, if it's overboosting and just had engine rebuilt, check your vacuum lines to the wastegate and make sure there hooked up properly and not leaking.

Edit to add:
Uh, just reread that 4000 and was okay. If new problem that was not there for the first 4K, it may be a bad wastegate actuator. Or already gone bad. But start with the easy.