The Throttle Position Sensor (TPS) is a potentiometer attached to the throttle shaft. A five volt signal is supplied to the sensor, and a variable voltage is returned to the ECM. The voltage increases as the throttle is opened.

A faulty throttle position switch (TPS) can result in a number of poor running problems. Because they can result in such a large number of problems, faulty switches often go undiagnosed. The other thing that makes TPS problems difficult to diagnose is that they quite often only appear when the engine is warmed up (throttle position switch warmed up).

The following lists some of the symptoms that MAY indicate a problem with the throttle position switch:

• Poor idle - particularly a high idle condition
• Engine cuts out to an idle condition during acceleration
• Poor power at various RPMs (various throttle positions)
• Surging idle
• Misfire
• Stumble during acceleration
• Intermittent boost problems (turbocharged cars)

Replacement and Adjustment

Normally Aspirated cars:

1. Remove the throttle body from the car.
2. Remove the two Phillips head screws that attach the TPS to the throttle body.
3. Install the new TPS and insert the mounting screws. Do not tighten the screws until the adjustment is complete.
4. Hold the throttle in the closed position and turn the TPS until the internal stop is felt and tighten the mounting screws.
5. Check the adjustment by turning the throttle toward the open position. An audible click should be hear as soon as the throttle starts to open. Slowly close the throttle until it is fully closed. Do not force the throttle closed. Allow it to close under spring pressure only. Just prior to going fully closed, an audible click should again be heard. If the click is not heard, readjust the switch.
6. Install the throttle body.

This 85-92 Throttle Position Sensor (TPS) is for your Camaro, Iroc, Z28, RS, Firebird, Trans Am, Formula or GTA