The throttle position sensor, or TPS, in the 22Re engine of your 1992 Toyota sends voltage signals to the engine computer to determine the angle position of the throttle plate inside the throttle body. Depending on the voltage signal from the TPS, the 22Re computer adjusts fuel volume delivery for better engine efficiency. If you suspect problems with the TP sensor, you can troubleshoot it at home without special equipment. This will help you diagnose a possible bad throttle sensor and save yourself in engine repairs costs.
Open the hood of your Toyota and locate the TP sensor. The sensor is a small, flat and rounded component with a four-wire electrical connector attached to it. It is secured to one side of the throttle body with two small screws. The air cleaner assembly, which houses the air filter, attaches to the throttle body towards the top center and rear of the engine compartment.
Remove the air cleaner assembly using a Phillips screwdriver.
Unplug the TPS electrical connector.
Locate the throttle linkage mechanism on one side of the throttle body. This mechanism connects to the accelerator pedal by a long cable.
Rotate the throttle linkage mechanism with your hand and see how the lever on the mechanism that hits a stop screw when you release it. As you rotate the mechanism, you will see the throttle plate rotating as well at the opening of the throttle body.
Insert a 0.0224-inch (0.57mm) feeler gauge between the throttle linkage lever and the stop screw.
Set your digital multimeter to the lowest setting on the Ohm's scale. Turn on the meter and touch the meter probes to the two lowest pin connectors on the TPS electrical connector. The display on your meter should register 0.0 or a similar low resistance value. Otherwise, you need to replace the TP sensor.
Replace the feeler gauge you inserted between the throttle linkage lever and the stop screw with a 0.0335-inch (0.85mm) feeler gauge.
Touch the two lowest pin connectors on the TPS electrical connector with the two meter probes again. Now, the display on your meter should show a blank screen or infinite resistance. Otherwise, you need to replace the TP sensor.
Turn off your digital multimeter. Plug in the TP sensor, replace the air cleaner assembly using the Phillips screwdriver and close the hood.
