Sheridon...
Hope it's all good now.

knight...
Vacuum leaks mostly affect idle, since that's when the manifold vacuum is strongest. Sudden sharp jerking makes me suspect ignition, where fuel or intake troubles are a little smoother. But that's not absolutely always true.

Look for arcing on your plug wires & distributor cap. Cold start in the dark, maybe spray water from a windex bottle to make it more visible.