is the a faulty BOV or something else?
 

ok, ive installed an aftermarket BOV (greddy type s) in my S4 T2 (jap version) on the pipe where the stock one was connected too. ive plugged up the hole in the intake etc. now after a while of being hooked up the car sometimes when started will stall, when accelerating sometimes it will hesitate for a second then go again.

is this the result of a faulty BOV or could it be something like a leak in the vacumm line or whatever?

any help appreciated:)