1995 Cadillac DeVille Concourse, 4.6 Northstar. Cannot find the IAT sensor! Have looked all around the intake boot, throttle body, air box, etc and cannot find it. The PCM says the IAT is bad (open or short). AllData indicates it should be located near the MAP and TPS sensors but, nothing in that arear and no harness or plug found either???

It is located in the air filter tube between the air filter box and the throttle body. Look for a 4 wire connector and that is it.

Look around the intake boot/air box area which goes into throttle body...should b a sensor around that area...check the little 2wire probably sensor if its plugged in..may need to b replaced..

Ok if you changed the idle air control and there are no certain vacuum leaks and your sure. This only means the intake intake manifold in the area of the IAC has A.carbon plugging it. B.A chunk is lodged in side the channel. I recommend cleaning your intake manifold with the best cleaner with AMSOIL or Seafoam and lets not forget the old trusty air compressor hose to to force the stuff out.
Also do the IAC reset procedure maybe the IAC was disconnected while the engine was running and this has made the PCM and the IAC out of sync.
Also the throttle position sensor needs checked as well to make sure it is idleing back and the butterfly is actually closing all the way in the throttle body. Carbon build up is common around the butterfly valve which causes it to stay open further.
Also lets not forget the Intake Air Temperature sensor.
All these items need checked and completed and eliminated from the list of what else it can be.
If I can assist you any further let me know
Please dont forget to rate my solution. Thanks in advance

The IAT (intake air temperature) sensor if it has one is in the air intake snorkle to the throttle body. But I`m pretty sure this year didn`t have one until 1997. If you mean IAC (idle air control) solenoid its on the side of the throttle body, black box with square 4 wire connector.

Hello: This model has a Northstar engine. The starter is under the intake manifold, you first have to remove the silver cosmetic cover then the intake manifold. Please disconnect the battery first.

4.9 engine sits on top of intake manifold toward the windshield. work s off engine vaccumn. Make sure it is getting vaccumn to check put car in gear hold foot on brake and oppen throttle briefly while you hold the open end of the line if working then the EGR solenoid is working. When you remove the valvr make sure there isn't any carbon build up blocking the flow of exhaust gases. remove throttle body there are two tubes make sure they are not plugged if engine is northstar valve is on driver side toward windshield on top with an electrical connector looks like ablack 4-5 inch can

The air temperature is taken between the air filter and the throttle body. Look in the roof of your air cleaner box. (usually 2-pin plug) After the air cleaner, the tube that sends the air to the throttle body has the mass air flow sensor in it.(usually 4-pin plug)

IAT stands for Air Intake Temperature Sensor and it is located in the intake tube coming from the air filter box tot he engine. Easiest way to find it is look at the top of your engine where it says 2200. Coming right out of that manifold is a black ribbed tube about the size of a baseball to softball. It should be going towards the direction on the front drivers side. on the back side of that tube, about 4 inches away from the intake manifold (the things that says 2200) is a plug with wires. That is your IAT Sensor. If it is unplugged, plug it back in. Otherwise unplug it and replace it. Make sure to disconnect the battery while you do this so the computer resets itself after the new one is installed. Thanks and please don't forget to rate!

Check your air intake duct & area or front area of throttle body . It should be sticking out a little inside hose or throttle body to sense incoming air.

The IAT sensor is most of the time located along the intake tube right after Between the throttle body and MAP sensor. Just follow your air intake tube from your air filter housing to the Throttle body.
Good luck.