I have a 78 242 B21F that starts but idles very rough until it begins to warm up. I did a "freezer test" on the aux air valve which when cold is only slighty open--a tiny crescent. I tried spraying cleaner and lubricant in it and physically opening it and allowing it to close with a small screwdriver. My question is: how far open should the gate be when the valve is cold? Should it open up at least halfway? All the way? I suspect my rough idle problem is at least partly because the cold start injector is working and the necessary extra air is not being provided on cold start. Comments please.