Primary Turbo dying?
 

Got my new GReddy 2-row in and had it tuned. We set the PFC for 15 psi, and it peaks at 15.1 psi, but then it drops all the way to 11.4 psi. Not too bad though. The car made 325rwhp @ 11.4 psi. We were thinking it's the primary, because it's not coming on in first gear too well. The secondary pulls like a stallion though. Another friend suspects the wastegate. Any ideas? BTW: They are stock twins.