i had this problem before and that is, every time i start the engine, once or twice max, the blow off valve makes the whoosh noise when revved and released gas pedal . however, afterwards there is no noise from the blow off valve and there seems to be a fluttering noise as if the pressure cannot escape.

the engine was old and giving trouble so i got an exact replacement engine and installed it. however since the new engine did not come fitted with a blow off valve but a by pass valve (made of plastic), i replaced it with my old blow off valve. however, the problem is still there.

i checked the vaccume connections, and it looks fine (fingers crossed).

i also do not see any way of adjusting my blow off valve like in after market ones