ive got a 90 spec s2 and ive chipped it with a collins performance chip and its got a pipercross filter and 3 in scorpin full system on it, i fitted a -31 actuator and wound the boost up to 15psi and all was well, now after going to pod for the central day and going up the strip i noticed the boost peaks at 16 and then creaps bk down to 12 and holds.

my car is still fitted with the amal valve so i'm thinking it may be this any1 come across this issue b4 and what do you all think is the best way to get it to peak and hold 15-16psi?

cheers