Just throwin the idea out there.

Edit - If i pull the vacuum hose of the BOV while the car is running and put it on my thumb i should feel the vacuum yeah?

Won't hurt the car if i leave it off for a sec while i blip the throttle to see the result?

Only reason i thought i'd ask is when the the car suffers the problem the exhaust is excessively "poppy" on the over-run after blipping the throttle, as well as struggling to start.