2007 chevy tahoe loses power

Code p 2165 refers to accelerator pedal position(APP) sensor C-maximum stop performance====causes wiring--APP sensor
also refers to throttle position (TP) sensor C -maximum stop performance===causes wiring --TP sensor it is possible that you may have other problems for the traction control and stability but if the system reports a particular code then that is what you have to fix first to eliminate the possibility that it is affecting other operations

No messaage of reduced engine power ? Your vehicle has electronic throttle control . Has four position sensors , two are located in the gas pedal ,an two in the throttle body . The PCM uses these sensor to know how much to open the throttle plate ,allowing more air into the engine . How did you read this code an where did you read it's definition at ? This is not a code for your vehicle . Some time cheap code readers get them wrong .
DTC P2120: Accelerator Pedal Position (APP) Sensor 1 Circuit
DTC P2122: Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage
DTC P2123: Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage
DTC P2125: Accelerator Pedal Position (APP) Sensor 2 Circuit
DTC P2127: Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage
DTC P2128: Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage
DTC P2138: Accelerator Pedal Position (APP) Sensor 1-2 Correlation

DTC P1516: Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance
DTC P2101: Throttle Actuator Position Performance
DTC P2119: Throttle Closed Position Performance
DTC P2176: Minimum Throttle Position Not Learned

If one of this position sensors is bad it will throw the PCM into a
Reduced Engine Power Mode
When the ECM detects a condition with the TAC system, the ECM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
• Acceleration limiting--The ECM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
• Limited throttle mode--The ECM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
• Throttle default mode--The ECM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
• Forced idle mode--The ECM will perform the following actions:
- Limit engine speed to idle by positioning the throttle position, or by controlling the fuel and spark if the throttle is turned off.
- Ignore the accelerator pedal input.
• Engine shutdown mode--The ECM will disable fuel and de-energize the throttle actuator.


017 Accelerator Pedal Position Sensors
Drive by Wire Function and diagnostics by Wells