If you have a Ford vehicle from the 1990s with electronic fuel injection, then it likely has a throttle position sensor (TPS) on the throttle body. The TPS is used to monitor the position of the throttle butterfly valve and sends a signal to the engine control unit (ECU) indicating how much throttle input is being applied by the driver. The ECU can then adjust fueling and ignition timing accordingly.
If your vehicle is running rough or the idle is unstable, one possible cause is a faulty TPS sensor. The good news is that calibration of a TPS sensor is relatively easy and can be done at home with some basic tools.
First, check your vehicle's service manual for the specific procedure as there may be slight variations depending on model year and engine type. Then, gather together a digital multimeter, an assistant and some patience!
With the engine off, disconnect the negative battery terminal to prevent any accidental shorts while working on live electrical circuits. Next, locate the TPS sensors electrical connector and unplug it. Using your multimeter set to ohms (Ω), measure between pins 1 and 3 of the connector - you should see close to 0 ohms resistance if the sensor is working properly. If not, replace the sensor.
Now it's time to calibrate the TPS sensor. With your assistant depressingthe accelerator pedal fully while you hold down pin 2 ofthe connector with one hand, use your other handto slowly turn pin 1 ofthe connector untilyou get acontinuity readingon your multimeter(this means that thereis low resistancebetween pins 1and 3). Onceyou've found this sweet spotwhere continuity existswiththe pedal fully depressed, tighten downpin 1 so it doesn't moveand askyour assistant topump upand release theatccelerator pedalseveraltimes so thatthe new settingcan take effect in thememoryof ECU . Reconnectbatteryterminaland startengine- id