GM Firebird 1967-1981 Repair Guide

Throttle Position Sensor (TPS)



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Test lead location for the C-4 system

This sensor is used only on 1980-81 models.

The throttle position sensor is mounted in the carburetor body and is used to supply throttle position information to the ECM. The ECM memory stores an average of operating conditions with the ideal air/fuel ratios for each of those conditions. When the ECM receives a signal that indicates throttle position change, it immediately shifts to the last remembered set of operating conditions that resulted in an ideal air/fuel ratio control. The memory is continually being updated during normal operations.