B2200 Idle Up Solenoid

When I turn on my a/c the idle up solenoid just pulsates the rpm. If I disconnect the plug to the idle up solenoid it stops. Any idea what may be wrong here?

Check the vacuum lines and the actuator diaphragm for leak or torn diaphragm.
If they are good, blow some air into the solenoid ports to clear the passage with the A/C on and plug connected.
If it still pulsates, check the voltage at the plug for pulsation. It should be a steady 12V.

Thanxs for the direction, I will try those steps..

I put a vac gauge/pump on the diaphragm and it will not hold a vacuum. lines are good so I think the actuator diaphragm must be bad.

Yes, diaphragm is bad. It should hold vacuum.