ill start off by saying that my bov is recirculated to avoid that as somones answer

HKS SSQV

ive always suspected my ssqv of leaking due to its 2+ yrs old..well i took it apart yesterday. Wut i found on the inside was kinda odd. The 2 valves on the inside had come apart..the bigger black valve has 4 peg holes that it sits in to keep it snug with the small purple valve...well the black valve was complety out of all the peg holes just hanging out in there not sealing properly when it would blow off so my next shift i would leak all the pressure out, so now i fixed that problem by seating the valve back into the peg holes and now it seals properly....BUT now when im driving i get this stumbling flutter noise between shifts it also feels like my car falls on its ass..while im boosting and i let off my RPMS will drop drastically between shifts(and yes it is recirculated) and i hate the way my car drives now when i shift it feels like i hit a brick wall..im not sure if this is comp. surge or just the nature of the BOV..but only other time ive heard this is sound is when i first put it in.

http://www.hksusa.com/content/pdf1583.pdf
good inside diagram of the ssqv