The TPS is a common source of headaches but usually is within the grasp of the shadetree mechanic to diag, adjusts, replace. Problems related to the TPS often show themselves as erratic idle and stalling at stop signs.

The throttle position sensor is mounted on the end of the throttle body and tells the computer how far open or closed the throttle is. The TPS is pretty easy to understand how it work’s, it is a potentiometer just like a dimmer switch.

Voltage is fed to the TPS by the signal return circuit. As the throttle is opened the TPS directs more voltage to the ECM and less down the voltage reference circuit. All of the following items will affect the TPS:

•Throttle Cable
•Throttle Body Cleanliness / carbon bulidup
•Vacuum leaks
•Air Filter condition
•Air Filter to Throttle Body Duct
•Engine condition
•Harness and wire general condition , connectors and grounds

The TPS sensor has a great deal of influence on the fuel ratios and timing curves, because the TPS is a user interface sensor.

The TPS is the closest thing you have to a direct line into the ECM.
The ECM listens to your every command from the TPS.

There is a TPS algorithm which continuously seeks the minimum throttle angle corresponding to a CLOSED THROTTLE position. This alleviates the necessity to set the throttle position sensor at an absolute position and compensates for system changes and differences between vehicles.