carb air leak?, occasioally surging idle Options

[VaccaRabite]

I am having a weird issue with my carbs.

They will go along fine at 1100 RPM idle all day. Suddenly I will stop at a sign or red light and the idle will climb from 1100 to 1700 and my car will start making unsynced carb noises. Sometimes it will settle back town if I tap the gas peddle, sometimes not. Once the idle surges, it will be like that for a while when I stop, and then it will suddenly drop back down to 1100 RPM and and behave nicely.

I am guessing that I have an intermittant air leak in one of my carbs. Anything else I need to be looking at?

My theories, in order of what I think is likely:
1) air leak somewhere
2) gas leaking past the inlet valve
3) weirdness with the linkage

I have not been able to recreate the issue at home, its always when I am on the road so I don't yet know which carb is acting up. Its worse if I am driving the car hard, but will happen when I am just cruising around town some too.

Ideas?

Zach