Ive encoutered a problem with my S2 erst , basically its not long after rebuild , and has not been set up yet but just now the car is fitted with 2 stage boost via a switch , and 10 psi low 14psi high , the car runs bayoo chip , piper cam/pulley , grs intercooler , bailey dump valve , mongoose exzaust system, been told should and could run more boost the problem is when i boost switch up or down , example , boost on high hits 14 psi goes great then gradually backs down to 10 psi , didnt use to b4 rebuild , now the turbo is in top nick and has a brand new -31 actuator on it , could it bean air leak or dump valve or needing a set up any help appreciated guys...

 

check the waste gate tension