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Dave Nova
Dave Nova, Chevrolet Technician
Category: Chevy
Satisfied Customers: 19452
Experience:  ASE Master Certification. GM World Class Certification
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Chevrolet Silverado 1500 reduced engine power message top

Resolved Question:

reduced engine power message top speed 30 mph gas pedal no response turn off engine and restart truck runs fine. It will do this 3 0r 4 times on 20 mile trip. Would a defective oxygen sensor cause this. Its a 2003 Chevy silverado 4.8 Engine.Only codes showing when read is P0449 and P0455. Any help would be appreciated.
Submitted: 6 years ago.
Category: Chevy
Expert:  Dave Nova replied 6 years ago.

Hello and thank you for using JustAnswer. My name is XXXXX XXXXX I will do my best to help you with your Chevy problem.


The Oxygen sensor will not cause this problem. This is normally a problem in the throttle control circuits. Either a fault in the pedal sensor or in the throttle position sensor in the throttle body. This will usually set other trouble codes.

Customer: replied 6 years ago.
Replace throttle body,rewire from computer to throttle body and and hook up to their diagnostic computer plus labor. How much would this cost and would it fix problem
Expert:  Dave Nova replied 6 years ago.

You definitely should start with an in depth diagnosis using the dealers scan tool. This usually runs $100-120.


If the problem ends up being in the throttle body, the replacement cost would be around $450.


If any wiring needs to be repaired/replaced the cost would usually be another $100.


Until you have the diagnostic done, you will not know for sure if the throttle body or the accelerator pedal position sensor or the wiring is the problem.

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