I got my Ford truck in a trade (I got the bad end) and trying to fix it up. I saw this sensor in the airbox and have no clue as to what it is. I have poured over all sorts of documentation including the factory service manuals and still nothing shows it to be there.

The people who I got the truck from in the trade, they put an Air Intake Temp sensor in the airbox as well, but according to the documentations of the truck, the sensor is suppose to be in the engine.

SPECS:
1994 Ford F-150
5.0L V8 motor
Automatic Trans
Single Cab

Pictures are of where it is mounted, and the sensor itself.

 

That's your ACT sensor. ACT as in Air Charge Temperature. Measures the temperature of the air coming into your engine.

 

That's part of the MAF (mass air flow) system which they started using with 302's in 94. Much better than the older speed density system.