Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Reduced Engine Power Mode When the PCM detects a problem with the throttle actuator control (TAC) system the PCM enters one of the following Reduced Engine Power Modes:
you may need to remove and clean the throttle body with carb cleaner,,these will get black soot and carbon in them sometimes and cause this,though the throttle actuator may be bad and need replaced
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THROTTLE BODY ASSEMBLY The throttle body for the TAC system is similar to a conventional throttle body with several exceptions. One exception being the use of a motor to control the throttle position instead of a mechanical cable. Another exception is the throttle position (TP) sensor. The TP sensor is mounted in the throttle body assembly. The TP sensor is 2 individual TP sensors within the throttle body assembly. Two separate signal, low reference, and 5-volt reference circuits are used to connect the TP sensors and the PCM. TP sensor 2 signal voltage increases as the throttle opens. TP sensor 1 signal voltage decreases as the throttle opens.
THROTTLE BODY ASSEMBLY REPLACEMENT REMOVAL PROCEDURE