What does it mean if your engine runs better when you make a vacuum leak? :screwup:

Also, on my holley 670 avenger carb when I turn the mixture screw on one side closed all the way, then engine noticably idles down, but when I turn the other one all the way in, nothing happens? When I turn both all the way in, it dies, like it should.

probably that you are running too rich, as a vacuum leak will lean it out. It also kicks the RPMs up though, so don't be fooled by something that sounds smoother if its only idling higher.

Sounds to me like you've got something plugging up the carb's idle circuit.