got a new blitz vta dump valve fitted to my 94 wrx took it out yesterday and stalled at the lights,adjusted the tension off on the adjuster nut at the top of the valve and the car does not stall now but is still not as smooth at idle as with the oe item,question is do i remove a little more tension bit by bit until its right or is there a actual correct setting for these,its approx 3 months old and the previous over fiddled with the adjustment.

 

AFAIK, these are set correctly from the factory, and playing with them can cause damage (as it can with any other BOV if you dont know what you're doing).