I have the same year thunderbird, auto, 3.8L V6. To get at the IAT sensor, you should have to remove the top of the engine (upper manifold or plenum). Refer to
www.autozone.com repair guides section for detailed instructions. It's easy with a couple of tools. Then you get the perfect view of it on the back side of the intake manifold. And the only sensor "by" the air box is in the intake tube, the Mass Air Flow sensor. Hope I helped!