Accelerator/Throttle stuck After heavy rains, everytime my activa's accelerator wire gets stuck and there is no way I can reduce the speed. Got it fixed from service center once, then ran into the same problem. This time took the help of the local mechanic but again ran into it. Any suggestions?

reduced engine power sensor ??? There is no reduced engine power sensor, Now a message on the DIC -driver information center, reduced engine power is a different story . Reduced Engine Power Refer to Powertrain Control Module Description in Engine Controls


Reduced Engine Power Mode
When the PCM detects a condition with the TAC system, the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
• Acceleration limiting--The PCM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
• Limited throttle mode--The PCM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
• Throttle default mode--The PCM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
• Forced idle mode--The PCM 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 PCM will disable fuel and de-energize the throttle actuator.

You need to hook up a scan tool an check for DTC'S - diagnostic trouble codes .

Reduced engine power is a problem with the electronic throttle control . You need to have a scan tool hooked up to read codes stored .

REDUCED ENGINE POWER: Refer to Powertrain Control Module Description in Engine Controls - 4.8L, 5.3L, and 6.0L

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:
• Acceleration Limiting--The control module will continue to use the accelerator pedal for throttle control, however the vehicle acceleration is limited.
• Limited Throttle Mode--The control module will continue to use the accelerator pedal for throttle control, however the maximum throttle opening is limited.
• Throttle Default Mode--The control module will turn off the throttle actuator.
• Forced Idle Mode--The control module will perform the following actions:
- Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.
- Ignore accelerator pedal input.
• Engine Shutdown Mode--The control module will disable fuel and de-energize the throttle actuator.

Switching on the aircon will rob the engine of a handful of horses but most people most of the time won't notice. Could be the problem goes deep.

By 2007 most vehicles were digital computer controlled so it isn't easy to guess what is going on. I think you need a guy with a good scanner who knows how to use it who can gather and interpret live data.

If you would like help we would need the DTC - diagnostic trouble code .Is their a Reduced Engine Power Mode message showing on the instrument cluster ?
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:
• Acceleration Limiting--The control module will continue to use the accelerator pedal for throttle control, however the vehicle acceleration is limited.
• Limited Throttle Mode--The control module will continue to use the accelerator pedal for throttle control, however the maximum throttle opening is limited.
• Throttle Default Mode--The control module will turn off the throttle actuator.
• Forced Idle Mode--The control module will perform the following actions:
- Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.
- Ignore accelerator pedal input.
• Engine Shutdown Mode--The control module will disable fuel and de-energize the throttle actuator.
IF you do not know this your best bet would be to take to a qualified repair shop .
DTC P0506
DTC P0507
The throttle actuator control (TAC) motor is controlled by the powertrain control module (PCM). The DC motor located in the throttle body drives the throttle plate. In order to decrease idle speed, the PCM commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the PCM commands the throttle plate open allowing more air to pass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this DTC sets.

It could be the APP sensors or the throttle body throttle position sensors . What DTC'S - diagnostic trouble codes . Need to test the electrical wiring , 5 volt reference voltage. Drive by Wire Function and diagnostics by Wells
REDUCED ENGINE POWER - mass airflow sensor has nothing to do with this problem .
Throttle Actuator Control (TAC)
Reduced Engine Power Mode When the PCM detects a condition with the TAC system, the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
?€¢
Acceleration limiting--The control module will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.

?€¢
Limited throttle mode--The control module will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.

?€¢
Throttle default mode--The control module will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.

?€¢
Forced idle mode--The control module will perform the following actions:

-
Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.

-
Ignore accelerator pedal input.

?€¢
Engine shutdown mode--The control module will disable fuel and de-energize the throttle actuator.

Refer to
?€¢
Powertrain Control Module Description for the 4.8L, 5.3L and 6.0L engine

Your Denali has Throttle Actuator Control (TAC) System - Electronic throttle control ! Are there any messages on the driver information center ? Reduced engine power ?
Reduced Engine Power Mode When the PCM detects a condition with the TAC system the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
?€¢
Acceleration limiting--The control module will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.

?€¢
Limited throttle mode--The control module will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.

?€¢
Throttle default mode--The control module will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.

?€¢
Forced idle mode--The control module will perform the following actions:

-
Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.

-
Ignore accelerator pedal input.

?€¢
Engine shutdown mode--The control module will disable fuel and de-energize the throttle actuator.

You need to have it checked for DTC'S - diagnostic trouble codes , probably a accelerator pedal position (APP) sensor or TPS - throttle position sensor !

Throttle Actuator Control (TAC) System Description
You have APP- accelerator pedal position sensors or one of the Throttle position sensors is going bad ! In the (TAC) system ! This is drive by wire or electronic throttle control . If you take it to the dealer or a ASE certified repair shop they can check the DTC'S - diagnostic trouble codes ! This is nothing for a DIYer to mess with ! This system can set 7 different DTC'S

Reduced Engine Power Mode When the PCM detects a condition with the TAC system, the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
?€¢
Acceleration limiting--The control module will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.

?€¢
Limited throttle mode--The control module will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.

?€¢
Throttle default mode--The control module will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.

?€¢
Forced idle mode--The control module will perform the following actions:

-
Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.

-
Ignore accelerator pedal input.

?€¢
Engine shutdown mode--The control module will disable fuel and de-energize the throttle actuator.


Drive by Wire Function and Diagnostics by Wells

Hi Steve , your vehicle has electronic throttle control . I don't know if you are aware of this. The gas pedal have position sensors an a wiring connector with 4-6 wires .these wires are connected to the engine computer . an there is a electric motor on the throttle body assembly , the computer opens an closes the throttle . You probably have codes stored in the engine computer .
Reduced Engine Power Mode When the PCM detects a condition with the TAC system the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
?€¢
Acceleration limiting--The control module will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.

?€¢
Limited throttle mode--The control module will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.

?€¢
Throttle default mode--The control module will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.

?€¢
Forced idle mode--The control module will perform the following actions:

-
Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.

-
Ignore accelerator pedal input.

?€¢
Engine shutdown mode--The control module will disable fuel and de-energize the throttle actuator.

Drive by Wire Function and diagnostics by Wells

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

Hi,

Sounds like you need to tune your carburetor and check the spark plug.
Try checking the CDi, replace it with an aftermarket racing CDi and compare the ignition and combustion, if it still doing that problem.

Tell us afterwards to guide you more of these problems.