Having stalling Problems on '90 Taurus

What is your question?

My 1990 Taurus 3.0 V6 has a problem of stalling/idling low. I have replaced the plugs and wires and a stuck Air Control Valve, but it still persists. I have gotten some people tell it could be Ignition Control Module, Pick up Coil and even the Ignition Coil. Any ideas as I am trying to keep from replacing parts unnecessarily.