I have a Chevrolet Silverado 2007 new body style saying that i have reduce engine power code p2138

Please just google this, GM fault codes P2138, P2123

You have a problem with the electronic throttle control . You need to have it checked for codes , could be a few different thing's Pt 1 2007 Chevy 2500HD Reduced Engine Power Warning Fault Code P1516... P2138 APPS Accelerator Pedal Position Sensor Fix 3 5L Chevrolet Impala Lot's of codes for this , Drive by Wire Function and diagnostics by Wells

2003 Silverado 2500HD REDUCED ENGINE POWER - Discussion on Topix

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Dec 28, 2009 - 20 posts - ‎12 authors I have replaced the throttle body, had the wires re-connected and .... The gauges all went wild and reduced engine power displayed on the dash. I looked it .... The truck just went to idle for no reason and it keeps happening. 2003 Chevy Trailblazer-CHECK ENGINE LIGHT AND ...
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Reduced Engine Power Message Displayed on GM Vehicles

www.underhoodservice.com/tech-tip-reduced-engine-power-message-dis...
Dec 10, 2012 - Tech Tip: Reduced Engine Power Message Displayed on GM Vehicles ... Model year 2008-'10 vehicles must have the engine control module (ECM) reprogrammed ... Do not drop the electronic throttle control components.

Hi Rosalee_IM,
The codes your vehicle is storing are for low voltage from your accelerator pedal position sensor and a gross evaporative emission leak. The code P2122 and P2138 are directing you to test the accelerator pedal position circuit and/ or sensor. This is the cause of the reduced power concern you are feeling.The P0455 is telling you there is a large leak in the evaporative emission system. The most common cause for this code is a loose or incorrectly installed gas cap.I hope this helps clarify the concerns you are experiencing. If you'd like more information on how to trouble shoot the problems,drop me a line. Please include the model Impala you have,(LS,LT or LTZ) and the engine size. I will do my best to get back to you as soon as possible.Thanks, Chuck

check your timing belt or chain

fuel filter is part of the fuel pump assembly

If you need further help, reach me via phone at https://www.6ya.com/expert/james_9c1b039055413ffa

There is a GM Technical Service Bulletin (TSB) on this issue, below is a summary;

#07-06-04-019A: Intermittent MIL/SES, DTC P2138 with Reduced Engine Power (Repair Instrument Panel (IP) to Body Harness Connector)

Models: 2005-2008 GM Passenger Cars and Light Duty Trucks (Including Saturn)
2005-2008 HUMMER H2
2006-2008 HUMMER H3
2005-2008 Saab 9-7X

Condition

Some customers may comment on an intermittent MIL/SES light Illuminated with a message center or an indicator that displays Reduced Engine Power. DTC P2138 - Accelerator Pedal Position (APP) Sensor 1-2 Correlation may be set. The voltage difference between APP sensor 1 and APP sensor 2 exceeds a predetermined value for more than a brief period. Refer to DTC P2138 in SI for further diagnostics.

Cause

On some vehicles, the IP to body harness connector, which carries the APP signal to the ECM/PCM, is located in the left hand kick panel area or inside the IP. Water intrusion into these areas could cause an electrical short in the APP circuits setting a P2138 code.

Correction

Note: Make sure that no add-on/aftermarket equipment is electrically connected to the APP signals or to the other ECM/PCM five volt reference or return lines. These can generate false P2138 and/or other ETC System DTCs. If there are other engine DTCs besides P2138, such as MAP sensor faults (i.e. P0107, P0108), resolve these first before attempting to diagnose P2138 DTCs.

Important: Refer to DTC P2138 in SI to confirm that the ETC pedal is operating correctly.

Locate the IP to body harness connector, which may be located in and around the left hand kick panel area or inside the IP. Check to see if there is a water leak into the area and repair as necessary. Use a water hose to determine the source of a water leak and effectiveness of repair. Some examples of potential water leaks are: A-pillar seals, sunroof drain lines (if so equipped) and windshield/cowl sealing. Finally, repair or replace the IP to body harness connector, making sure no corrosion or debris is left on or between the terminals.

Condition:
Some customers may comment on an intermittent MIL/SES light Illuminated with a message center or an indicator that displays Reduced Engine Power. DTC P2138 - Accelerator Pedal Position (APP) Sensor 1-2 Correlation may be set. The voltage difference between APP sensor 1 and APP sensor 2 exceeds a predetermined value for more than 2 seconds. Refer to DTC P2138 in SI for further diagnostics.

Cause:
On some vehicles, the IP to body harness connector, which carries the APP signal to the ECM/PCM, is located in the left hand kick panel area and if the kick panel is not sealed properly, water enters and causes a short in the APP circuits setting a P2138 code.

Correction:
Important: Do Not replace the accelerator pedal assembly.

Locate the IP to body harness connector, which may be located in and around the left hand kick panel area. Check to see if there is a water leak into the area and repair as necessary.

Replace your throttle position sensor, runs about $60.00 sit on throttle body has a round connector with three wires going o it.

There is a GM service bulletin on this particular item. basically covers both codes your getting.
#07-06-04-019A: Intermittent MIL/SES, DTC P2138 with Reduced Engine Power (Repair Instrument Panel (IP) to Body Harness Connector)

Models: 2005-2008 GM Passenger Cars and Light Duty Trucks (Including Saturn)