Eh, do you have a way to monitor your A/F ratio?
You might want to post over in the FI forum, and provide a link to this thread. It sounds to me like you have some sort of leak in the IAC body. When you disconnect it, it should force the plunger closed through the spring action cutting off air to the leak. It's probably the vent for the diaphragm that is leaking, so yes, you just need a new one.
The diaphragm dent is that little button that is on top of the IAC, you might be able to feel your vacuum leak there if you can get your hand on it.
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Originally Posted by the user formerly known as ZX3_Chick
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