If the IACV is stuck or broken, the idle would fluctuate up and down. ODDS are this is not the problem. It still could be, but odds are against it.
If the car just dies with your foot off the pedal, it is likely a vacuum leak. Check hoses and clamps. Pay special attention to -
1. Any hoses that plug into a PCV valve or connect the air cleaner to the valve cover.
2. Any hoses that plug into the EGR valve.
3. Plugged PCV valve
If you don't know what you are looking at, either the car manual or a sticker under the hood should show you how the emissions system should look when connected properly. Follow all hoses and check for cracks, leaks, busted clamps, etc.
Many cars use a second cable that connects to the throttle body. Its part of the throttle assembly and allows the computer to control the idle speed. If this has slipped or is cracked, replace it.
Check your throttle position sensor. It is an electrical sensor that is plugged in next to the throttle body. Pull the cable connector and spray the plug clean with brake cleaner (dont get it on the paint).
Finally, if you think it is the IACV, check the hoses to it first. Replace if they are cracked. If that's not helping, pull out the air intake, throttle brackets/cable, throttle body, and disconnect the IACV (idle air control valve). Spray it clean with brake cleaner and reassemble after the parts have completely dried.
