Any thoughts on this?

[foca_]

Hi there,
I am experiencing a sudden drop in manifold pressure. Looks good until 6000rpm or so, then it drops and stays at 2 psi.
Turbo is in good shape - i changed it, same thing happened with the old one
Pop off connections are fine, double checked it, even tried a different brand, same problem
All plumbing is fine, not tear or wear
I have checked datalogs over and over and cant find a reason this could be happening. I thought it could be due to VTC set at high angles, so i tried different setups closer to 0 on the upper half of the rpm... problem persists.
I really cant find the issue, is it possible (although this sounds stupid) for the TB to be closing some degrees? Datalogs show a perfectly working TB, but i dont know about that...
Any help at all will be much appreciated