I've moved my Quadrajet carb from my blazer to my new suburban and when I started it up the idle is very low. Only difference between the trucks is that the suburban doesn't have A/C so it doesn't have the little plastic vaccum-tank for that. I plugged that vaccumport but can this really affect the idlespeed or did I mess something up? Offcourse the easiest fix is just to turn up the idlescrew but I like to know what causes this before I do that. Anyone have an idea what's wrong?