July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Vacuum Switch Valve

Remove Vacuum Switch Valve (VSV) from vehicle. Apply vacuum to the diaphragm nipple. Blow through either port "A" or "B". See Fig 1 .
VSV should be closed when vacuum is below 2.6 in. Hg and open when vacuum is above 4.2 in. Hg. If the VSV does not function, replace valve.

Fig 1: Testing Vacuum Switch Valve

Courtesy of FORD MOTOR CO.