Here is some more in-depth info and some more specific info on the tests you can do.
Carefully disconnect the vacuum lines from the valves (on the hose) and see if the valves hold vacuum, if not replace. If they do, disconnect the vacuum lines from the solenoids, hook up a vacuum pump to the top port and do a KOEO test. At the end of the test the TAB/TAD solenoids will cycle on/off when you move the throttle plate (you'll hear them click). Apply some vacuum. Your test light should come on/off when you move the throttle plate and the vacuum gauge should bleed off. If you don't hear them cycle on/off, check for ground at the connector(s). The puter only provides the ground as a switch. If you have good ground and the vacuum still holds then the solenoid(s) are bad-->replace. If you can't get the vacuum to hold on either solenoid, check for vacuum leaks on the plastic vacuum lines or at the black connector.
Friday, October 7th, 2011 AT 1:52 AM