idle trouble with coast vent valve quick help needed please

[jay]

hi, car's getting setup tomo in sanspeed in bexleyheath but i was trying to get it best i could over weekend as its wasnt ideling properlly,the timing was a bit out etc but my trouble is the coasting vent valve(economy thing big gold cylinder comes off inlet goes somewhere) whens its connected even when the idle screws wound right in it idles its bollox off and you can slow it down,i spoke to just novas and corsa's they said try disconnecting it so i blanked it off and it slowed right down and idled how it should on the idle screw,does this mean its buggered or just needs adjusting and do you think they'll be able to do it because i dont want to get there to find out i have to come away to get a new one and start again,can anyone help? i read the haynes but i dont have a vacum to measure it or anything! its weird i'm sure it was ok before i had to do the head gasket and also a new TB at the same time(TPS iffy)

thanks for any help,

james