Hey would a leaking BOV cause the same issues as a vacuum leak. I have the HKS SSQV and started running like crap after putting on the recirculation. Not that it has gotten cold around here the car runs pretty good except at idle it misses as if there is a vacuum leak but its stays around 700rpm and dosn't dies. Runs good under boost if I feed the throttle in ( can't just hop on it, especially when trying to down shift to overtake someone). I've tested it with 3 other AFM ( I was getting a code 31). The original and the 3rd I have are good.