Ok, Rusty and I put on the Ported Plenum and after putting it on and having a short race with each other, my SES light came on. We checked the code and its code 23. TPS Sensor Error OR Low Temprature at Intake Manifold Air Sensor (IAT) Well, after Randy M, and Rusty both searching through the Helms manual have come to the conclusion that the 92 Z28 doesnt have an IAT (unlike the 91 which has it on the air box) and i checked the voltage at the TPS and its fine. I even put it back to the stock position. .58v at idle and 4.00 at WOT. The light seems to come on when the temp in the engine gets to running temp. We are stumped as to what it can be. Any ideas? and if there IS a IAT sensor on my 92 speed density(camaro), WHERE IS IT??? The only sensor that was swapped or even touched durring the swap was the MAP sensor on the bottom of the plenum. HELP! PS. Car runs great, no problems even with the light on.

 

The IAT sensor you are looking for is under the plenum at the rear
just inboard of the map sensor.

 

The 91s had a "MAT" sensor- MANIFOLD Air Temp. It's position was correctly described in the above post. Same thing, basically as an IAT INTAKE Air Temp sensor, but they call it a MAT because it's screwed into the intake manifold (plenum) on TPI motors. You likely just left it unplugged or it popped back out during installation somehow. It's very common to have it kick a code only after a hot cycle (around the time the cooling fans come on).