The IAC on a '96-97 4.6L is exceptionally easy to get to. Disconnect the electrical connector, disconnect the air tube, and remove the two bolts attaching it to the front of the plenum.
Yup, 5 minute fix. Unhook the connector and you have clear sailing.
Make sure you get a Motorcraft part, the third party ones don't seem to last.
97 Thunderbird LX (The GT Bird)
PI Swapped NPI motor with some port work on the heads, PI cams, 80mm MAF, CAI that feeds from fenderwell. Jmod, 3.73:1 TL in Mark VIII carrier, Mark VIII aluminum LCAs, 93 Mark VIII driveshaft, PBR brakes (soon to be Cobras), 18x9 wheels, 255/40/ZR18 Tires, Front and Rear strut/shock bracing, GR-2 shocks, Eibach 1.5" springs, 1989 SC front and rear sway bars.