Q: Reduced engine power on GMC Envoy 2003

asked by on April 19, 2017

The Reduced engine power light come on while I'm driving and reduces my speed for a minute then I'm able to pick up speed again until I stop at a light I something, once I accelerate again I pull off very slowly
My car's transmission is unknown to me.

Reduced Power light is on Inspection $79.99 - $89.99 Get a Quote

The issue you are writing in about is common enough that a specific diagnostic, namely a Reduced Engine Power Warning Light Diagnostic is performed by technicians dispatched by YourMechanic. If you request that diagnostic, the responding certified mechanic will get this issue resolved for you. In your circumstance, the vehicle’s powertrain control module (PCM) has undoubtedly stored one or more diagnostic trouble codes that will identify the "general area" in which the fault lies in the engine management controls. Although the throttle control system is a common trouble area when the Reduced Engine Power Warning Light illuminates, there are quite a few other components and systems that could come into play and, of course, there is always the possibility of multiple, or "coincident", faults. Here are some of the possibilities that YourMechanic diaspatched technicians would consider:


Defective throttle position (TP) sensor
Defective oxygen sensor
Defective accelerator pedal position (APP) sensor
Loose or damaged wiring
Defective throttle body
Defective powertrain control module (PCM) (not typical; ONLY if a long, long list of other possibilities is ruled out)
Any fault/error that will affect drivability function
Any fault/error that will affect vehicle performance
A fault/error in the emissions system
A fault/error in the throttle control system
A fault/error in the transmission control system


The Reduced Engine Power Warning Light is considered serious because of the immediate and severe drivability problems that will be present until the engine or transmission fault is repaired. If you request the recommended diagnostic the mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

I bled my clutch master cylinder and now how do I get my clutch pedel back up after bleeding Master Clutch Cylinder? Wha asked by

If you refer to YourMechanic's on-line clutch system tutorial you will see that there are four possible reasons why the clutch pedal would fail to return, namely: 1) a failed clutch release bearing; 2) a failed slave cylinder; 3) a...

I wana purchasw this jaguar x type 03 but transmiasion only works in reverse dont know anh thing about transmissions so a few poi

Hi Paper T. Thanks for contacting us tonight. This type of transmission problem is commonly due to inner seal damage or other internal component failure. Unless you're ready to replace the transmission or able to completely rebuild, you might want...

Brakes unresponsive only one time

Inoperative brakes are a definite safety concern. If it happened once, it will happen again. Unfortunately, if the vehicle isn't currently acting up, it may be difficult to diagnose. The mechanic is correct that the most likely cause of your...

2003 gmc envoy ignition got broken from someone and i need to drive it how can i bypass the anti-theft locking system???

The anti theft system is integrated in the engine and body computers and cannot be bypassed. You will need to replace damaged component and if you have original key the system will start with old key held next to new...

Engine idle fluctuates and dies.

This may be a couple of different things. Your truck has what is called a throttle position sensor. The throttle position sensor is a sensor used to monitor the throttle position of the throttle plate inside the throttle body in...

Car vibrating when accelerating

Depending on the vibration, this can be caused by broken engine mounts. The mounts are meant to absorb the vibration of the engine as it runs. When mounts break, the rubber that absorbs the vibrations can break off completely and...

Where can i find my cabin air filter on my 2006 Buick Rainier?

If the vehicle is equipped with one, you can find it by lowering the glove box and looking behind it for the filter cover. Remove the cover and filter will be inside. If you find that the cover is not...

Idles high without accelerating

Hello. Thanks for writing in about your 2002 GMC Safari. There are several components that may be causing this problem. There could be a bad throttle position sensor, a throttle cable that is sticking, or a vacuum leak. All of...

Regarding electronic brake control module

Check the brake light bulbs, sockets and grounds first - they endure the most harsh conditions, and are easiest to check. Given the "intermittent" condition you mention, the brake light switch itself, and the brake light relay are next on...

Related articles

2012 Chevrolet Equinox vs. 2012 GMC Terrain: Which One Should I Buy?
The mid-size crossover SUV category offers the comfort and size of an SUV, but on the platform of a car, giving it the look and feel of a large hatchback. The unibody construction typical of passenger vehicles is used instead...
Top Five Selling Cars in Colorado in 2012
Colorado Colorado offers a varied climate depending on where drivers are located. Those in lower elevations see plenty of sunshine all year, while those in the mountain areas can see as much as 300 inches of snow. Due to this,...
The Best Used Cars to Buy If You’re Over Six Feet Tall
While While shorter than average drivers can have a tough time finding the right car, it’s equally hard for taller drivers, perhaps more so. If you’re feeling squished, or have to hunch over the wheel to drive, then you’re not...