I have been searching for the information on which resistor a guy should use to send a cold air reading to the ecm. I now that the ecm sends 5 volts to the intake air temp sensor, and that the sensor adjusts voltage to the ecm depending on air temp. The colder the air, the higher the resistance or lower voltage. But what voltage is the IAT sending to the ecm when it is reading cold air.

 

5 volts. It's the current that changes. E=IR

 

you dont want to do this... your ecm needs that calculation to meter the fuel correctly. any gain in one small instance will be completely wiped out by power loss in every other.