The TPS (Throttle Position Sensor) in your 5.0 Mustang is a variable resistor that the on-board computer uses to calculate engine load for fuel and ignition system control. A 5 volt reference signal is supplied to the sensor by the computer and as the throttle is opened the resistance of the sensor changes causing the voltage returning to the computer from the sensor to vary. Adjust the sensor to provide accurate return voltage to the computer and restore lost performance or fuel mileage caused by inaccurate computer control.
Start the engine and allow it to reach normal operating temperature on the temperature gauge. In the 5.0 liter Mustangs normal range is typically reached when the gauge needle is between the "R" and the "M" in the word "Normal" printed on the gauge. Turn the ignition off.
Attach the digital volt/ohm meter to the sensor's return signal (green wire) and engine ground. To attach to the signal return wire push the probe end of the red meter lead into the back of the TPS sensor's electrical connector until you feel it contact the terminal inside the connector.
Turn the ignition key to the "On" position and set the digital volt/ohm meter to the volts D?C range. Observe the voltage shown on the digital volt/ohm meter. Correct voltage for the 5.0 Mustang TPS is .98 to .99 volts.
Loosen the two screws that attach the TPS to the side of the throttle body. Rotate the TPS in the throttle body until the voltage on the meter reads .98 to .99 volts. Hold the TPS securely and re-tighten the screws.
