How to Improve Gas Mileage on a V8 Sierra

by Vanessa Padgalskas

According to, the GMC Sierra with a V8 gets roughly 12 miles per gallon in the city and 18 on the highway. GMC has five models of the Sierra: 1500, 2500HD, 3500HD, Denali, and Hybrid. The Hybrid V8 gets 21 miles per gallon in the city and 22 on the highways.The Sierra is a large truck with a powerful engine, but you can improve its gas mileage by changing your driving style and making changes to the truck.

Step 1

Go to a mechanic for scheduled maintenance. Click on the link "GMC Maintenance Schedule" under "References" at the bottom of this page and input your year and model of Sierra. This will show you what you need to have inspected at certain mileage intervals.

Step 2

Get regular oil changes every 3,000 miles. Changing the oil is one of the easiest ways to maintain the health of your engine. Oil becomes thick over time, and the engine needs to use more power to move the oil through the motor, which reduces fuel economy.

Step 3

Consider installing Eibach Springs on your Sierra. Eibach Springs reduce drag and improve all around performance. They have been shown to improve fuel economy, especially on pick up trucks like the Sierra. Click on the link "Eibach Springs" under "References" for more information.

Step 4

Change your driving style. Do not accelerate quickly from a stop. Set your cruise control on a speed no higher than 65 to 70 on the highway. Driving at high speeds reduces fuel economy. If you anticipate a stop ahead, let up on the gas and glide to a stop rather than accelerating and having to slam on the brakes. The Sierra is a heavy vehicle and takes a great deal of power to propel. Altering your driving style is one of the best ways to improve your miles per gallon.

Step 5

Remove excess weight from the truck and tow as little as possible. Although the Sierra is made for hauling and towing, these activities use extra power, causing the Sierra to get fewer than its estimated miles per gallon.

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