I have diagnosed my problem with the IAT sensor to be in the ECM. Checked grounds, power, resistance, wiring harness from ecm...etc.

I replaced ECM, and not suprising, the sensor still reads 180 f when the ambiennt temp is around 60. The sensor works, resistance changes, but the ECM responds the wrong way.

I'm almost certain the fault is in the EPROM chip. The dealership had no clue if they reflash the chip or replace. It seems to me the problem followed the chip to the new ECM.

SO my question is on 93's when replacing the ECM does the prom get updated or replaced?