I really need some help on this topic. I can't seem to get my Holley 5200 to idle low enough when cold without shaking the entire car, but still not run to rich. Every time I think I've got it, I check my MPG and I'm only getting around 16 MPG, that's even after a carburetor rebuild! I am using a vacuum gauge that my dad has had for awhile. I aim to have the vacuum at about 20, but I can only get it to about 17-18 without it either burning to rich or idling way to high.
Anyone?