How do you test idle air control and throttle position sensor 97 4.6 ford?

To test the Idle Air Control (IAC) valve on a 1997 Ford 4.6L engine, first, ensure the engine is off, then disconnect the IAC connector and check the resistance across the terminals with a multimeter; the resistance should typically be between 6-12 ohms. For the Throttle Position Sensor (TPS), with the ignition on (engine off), measure the voltage across the sensor terminals; it should range from about 0.5V at closed throttle to around 4.5V at wide open throttle. If the readings are outside these ranges or inconsistent, the components may need replacement. Always refer to the specific service manual for detailed specifications and procedures.