need help on a boost issue

[yuh8tng]

my 40 was sittin for about a year and i just got her back on the road again. i just did the PCV kit install, running very well after install also did alot of maintence work like new plugs, plug wires, oil change, cleaned MAF n k&n air filter but i also took apart my MBC and cleaned it. after re-installing MBC n adjusting wastegate actuator lower. well when i took it for a test drive it ran very well but when i would give it half throttle or more at 10psi boost the turbo would sputter til i left off the throttle. i began to try different wastegate actuator settings and different boost settings but it still continues to do the same sputter when it hits 10psi boost. i also tryed to swap out my MBC with another MBC but still have the same results. i dont get a CEL and she runs very good n spools up very good. i know i could of easily done some searching on the old s40 site n a topic would of came up that would help diagnos my problem soo now im asking for any suggestions or advice from our 40 community members. im thinking maybe my wastegate actuator went out or maybe my CBV went out (also my CBV has the quater trick installed) any help would be appreciated

[TEEKAY]

Sputter immediately makes me lean towards CBV diaphram.

[yuh8tng]

Thank you TEEKAY for your reply and suggestion. i kinda was thinkin towards the CBV because about 2 yrs. ago when i did the quarter trick on the CBV i was gettin a slight sputter but when i put the quarter in the CBV it went away. ive been noticing since ive done PCV kit install that ive had to check and replace vacuum hoses, tighten IC clamps and basically double check all my mods that ive done. everything is good but the one thing i know for sure that needs to be fixed is my flex pipe. my flex pipe has an exhaust leak but its been like that since even before i did the PCV kit install

im take apart the CBV rite now. hopefully cleaning it well help or ill be able to see if the diaphram is bad