Refuses to idle, CEL is on

My wife's 02 Tribute V6 has had the CEL on for a few months, but no real drivability issues.
Today, it refuses to hold an idle.
She starts fine, but take your foot off the gas, and the revs drop off and the car dies every time.

Dealers are closed due to Thanksgiving, so I'll coax the truck over in the morning.

Does it sound like an O2 sensor or is there something common on the V6.
Truck has about 60000 miles on it.

Thanks in advance.

Just a thought ... if its the idle air control valve, is this expensive?

Got the car back from the dealer.
They've ordered the IACV, and cleaned up the EGR.
The charge will be just over $300 ... yikes.