98 Contour Duratec v6, Stalls at idle

So I'm really looking for any help I can get here, I'm working on my girl's car which is a 98 Contour, 2.5L Duratec V6 in the non-SVT model. My problem is that the car will stall any time it enters idle. I can start the car if I give it a little bit of gas at the same time, and it will continue to run (within the full RPM range all the way down to approximately 350) as long as I give it some gas. The car stalls immediately when pressure on the gas pedal is removed.

In my attempts to fix the problem I have:
- Put a gasline antifreeze with Ethynol Glycol into the tank
- Changed the plugs and wires
- Changed the air filter
- Changed the pcv valve
- Checked the IAC sensor (clicks appropriately when power is administered, did not test resistance)
- Checked the Fuel pump / sending unit (initializes upon advance of key in ignition)

Any advice as to where should I go from here? I'm trying to save her as much money as possible as we're both still students. It definitely doesn't help that I've only ever worked on GM vehicles before now either. Thanks in advance to anyone who replies.

You may just want to replace the IAC. It may still be getting power, but the problem is that carbon build up causes the valve to stick.

You may have a vacuum leak.