How good is the GMC Sierra 1500’s fuel economy for Oklahoma City drivers?

The GMC Sierra 1500 is good on gas for a full-size truck, and the engine you choose decides how good. GMC rates the 2026 Sierra 1500 between 15 and 25 mpg combined, and Bob Howard Buick GMC in Oklahoma City sells it new. Oklahoma City drivers get closest to those ratings by matching the engine to their commute, and the city and highway numbers show where each truck does best.

Keep reading below, then schedule a test drive in Oklahoma City. Bringing your own numbers to the lot settles this faster than any spec sheet.

The GMC Sierra 1500 gets good mpg in Oklahoma City with the right engine

GMC’s EPA certified ratings put the 2026 Sierra 1500 between 15 and 25 mpg combined, depending on engine and drivetrain. The engine you pick sets where your truck lands in that range, and Oklahoma City traffic and speed move it from there.

The 3.0L Duramax diesel sits at the top of the range, rated 25 mpg combined in 2WD. The 2.7L TurboMax and the 5.3L V8 are the gasoline engines most daily drivers will weigh against it. In 2WD, the TurboMax rates 20 combined and the 5.3L V8 rates 17. The 6.2L V8 comes in 4WD only, and the AT4X version rates 15 combined.

Bob Howard Buick GMC sells the Sierra 1500 new at 13300 N Broadway Ext, so you can match the engine to your route before you buy.

GMC Sierra 1500 mpg by engine for Oklahoma City buyers

The 3.0L Duramax diesel carries the highest EPA combined rating in the Sierra 1500 lineup, at 25 mpg in 2WD. Oklahoma City buyers who spend most of their time in town should look at the city column first, because that is where the diesel leads by the widest margin. The 3.0L Duramax diesel 2WD rates 23 city, 7 mpg above the 5.3L V8 2WD.

GMC’s EPA certified ratings for the 2026 Sierra 1500, by engine and drivetrain, in mpg:

The diesel also has the best highway figure in the table, which matters for Interstate and turnpike miles. The gasoline engines sit closer together, so the drivetrain you choose changes their numbers more than the engine does.

How does Oklahoma City traffic change GMC Sierra 1500 mpg?

Texas A&M Transportation Institute counted 19 extra gallons of fuel per Oklahoma City commuter in 2024 spent sitting in congestion (Texas A&M Transportation Institute, 2025). Commutes on I-44, I-35 and the John Kilpatrick Turnpike are mostly stop-and-go and highway merging, so the city rating matters most for a daily truck.

The John Kilpatrick Turnpike averaged 76,748 vehicles a day in 2025 (Oklahoma Turnpike Authority, 2026). In that kind of traffic, the 2.7L TurboMax 2WD rates 18 city, and the 4WD version rates 17. The 5.3L V8 2WD rates 16 city, so a driver who spends hours in stop-and-go traffic gains the most from the diesel’s 23 city rating.

How do Oklahoma wind and turnpike speeds affect Sierra 1500 highway mpg?

Aggressive driving can cut gas mileage by roughly 15% to 30% at highway speeds (Many Factors Affect MPG, fueleconomy.gov). Speed is a separate cost, and it is one you control.

Each 5 mph over 60 mph costs about 7% of fuel economy (U.S. EPA and DOE, 2026). Higher speeds also mean more wind resistance, which lowers mpg, and the EPA’s tests account for drag only up to 80 mph (Many Factors Affect MPG, fueleconomy.gov).

The Sierra 1500’s highway ratings run from 16 to 28 mpg in the EPA table. The 3.0L Duramax diesel 2WD rates 28 highway, the highest in the lineup, so a driver who covers long highway stretches gets the most from that engine.

What do lift kits, big tires and 4WD do to Sierra 1500 mpg?

The 2.7L TurboMax drops from 20 mpg combined in 2WD to 18 in 4WD. The 5.3L V8 shows the same pattern, from 17 combined in 2WD to 16 in 4WD. That gap is the price of the drivetrain, and it shows up on every gasoline engine with both versions.

Off-road tires cost mpg too. The 2.7L TurboMax with Mud Terrain tires rates 17 combined, one mpg below the standard 4WD version. The AT4X 6.2L V8 rates 15 combined, the most demanding setup in the 4WD rows.

Weight also takes a toll. An extra 100 pounds can decrease fuel economy by about 1% (U.S. EPA and DOE, 2026). Rooftop cargo adds drag on top of weight: a large, blunt rooftop cargo box can reduce fuel economy by 6% to 17% on the highway and 10% to 25% at Interstate speeds (U.S. EPA and DOE, 2026).

What does fuel cost per year for a Sierra 1500 in Oklahoma City?

Yearly fuel cost is your annual miles divided by the truck’s mpg, times the price per gallon. Regular gasoline averages $3.87 a gallon in the Oklahoma City metro (AAA, 2026), and diesel averages $5.85 a gallon there (AAA, 2026).

All of the figures are hypothetical. It assumes 15,000 miles a year, $3.87 a gallon for the gasoline rows, and $5.85 a gallon for the diesel row.

The diesel uses the fewest gallons, but its higher price per gallon closes most of that lead. In this example it costs about $95 more a year than the 5.3L V8 2WD, and about $600 more than the 2.7L TurboMax.

How can Oklahoma City drivers get better mpg from a Sierra 1500?

Choosing the engine that matches your daily miles does the most for mpg. Idling and short trips add fuel use on top of that.

Idling burns fuel without moving the truck at all, and fueleconomy.gov lists idling at 0 miles per gallon (fueleconomy.gov, 2026). Several short trips also use more fuel than one combined trip (fueleconomy.gov, 2026), so combine errands when you can.

Cargo matters too. Rear-mount cargo boxes or trays reduce fuel economy by 1% to 2% in city driving and 1% to 5% on the highway (U.S. EPA and DOE, 2026). Carry only what the trip needs.

FAQ

What fuel does each GMC Sierra 1500 engine use?

Most Sierra 1500 engines run on gasoline, including the 2.7L TurboMax and the 5.3L and 6.2L V8s. The 3.0L Duramax runs on diesel, and the 4WD flex-fuel version with the 5.3L V8 runs on gasoline or E85. Its EPA label rates it 15 city, 19 highway and 17 combined.

What happens to Sierra 1500 mpg on E85 fuel?

Flex-fuel vehicles get about 15% to 27% fewer miles per gallon on E85 than on regular gasoline (Flex-fuel Vehicles, fueleconomy.gov). Ethanol holds less energy per gallon than gasoline, which is why the mileage drops.

How much does towing a trailer lower Sierra 1500 mpg?

Towing a trailer or carrying heavy loads decreases fuel economy (Many Factors Affect MPG, fueleconomy.gov). The 3.0L Duramax diesel in a Crew Cab short bed 2WD is rated to tow up to 13,100 pounds, the highest max towing figure in the Sierra 1500 lineup.

How does GMC Canyon mpg compare with the Sierra 1500?

The Canyon 2WD rates 20 combined, the same as the Sierra 1500 2.7L TurboMax 2WD. The Canyon 4WD rates 19 combined, one mpg above the Sierra 1500 2.7L TurboMax 4WD at 18.

How are the EPA mpg ratings on a Sierra 1500 sticker measured?

The city test represents stop-and-go urban driving with a cold engine. The highway test represents a mix of rural and Interstate driving with a warm engine in free-flowing traffic. The combined rating weights the city figure at 55% and the highway figure at 45% (U.S. EPA, 2026).

Which GMC Sierra has the best MPG?

The 3.0L Duramax diesel 2WD has the best mpg in the 2026 Sierra 1500 lineup, rated 23 city, 28 highway and 25 combined. The 3.0L Duramax diesel 4WD with Sport Mode rates 24 combined, so the diesel leads in both drivetrains. Among gasoline engines, the 2.7L TurboMax 2WD is highest at 20 combined. If most of your miles are in Oklahoma City traffic, start with the diesel’s city rating, then compare engines on the truck itself at Bob Howard Buick GMC, 13300 N Broadway Ext.

Why start your Sierra 1500 search at Bob Howard Buick GMC in Oklahoma City?

Bob Howard Buick GMC is a Buick and GMC dealership at 13300 N Broadway Ext in Oklahoma City. We sell new, used and certified pre-owned vehicles, and we run a full service, parts and financing operation. We are part of Group 1 Automotive, the parent company behind our store.

Our new lineup includes the Sierra 1500 and Sierra HD, plus the Yukon, Acadia, Terrain and Canyon in GMC. Buick’s Envista, Encore GX, Envision and Enclave round out the SUVs we sell.

Our Google rating is 4.4 stars across 3,983 reviews, and 79 in 100 of those reviews are five-star. Customers describe their experience in their own words. In a July 2026 Google review, Reace W. wrote: “Worked with Eddie at Buick gmc, he was absolutely amazing. This dealership is lucky to have a sales person like him. Hard to find such a reliable and trustworthy person or dealership these days! I’d be more than happy to purchase from this group for future vehicles. Thanks, Eddie!” In a July 2026 Google review, Melissa Z. wrote: “Edward was very helpful and super responsive. He found us a great van and we are very happy!”

You can reserve a test drive online or by contacting us. Start with the GMC truck inventory, value your trade, get pre-approved online, then finish in store at 13300 N Broadway Ext. Start with the GMC truck inventory at Bob Howard Buick GMC.

Bob Howard Buick GMC answers this question against the specific vehicle in front of you rather than the model in general. Value your trade and get pre-approved online, then see us at our Oklahoma City showroom, or call (405) 928-0697.

Disclaimer: Vehicle features, specifications, pricing, options, and availability may vary based on production timelines and dealership inventory; images are for illustrative purposes only. Starting MSRP figures are national and exclude destination freight charges, tax, title, license, and dealer fees. Standard and available equipment varies by trim, configuration, and model year; confirm the specification of the individual vehicle before purchase. Maximum towing and payload ratings depend on cab, bed, drivetrain, and equipment configuration; see the vehicle’s Owner’s Manual and trailering guide for limits. Electric range and charging times vary with battery, configuration, temperature, terrain, load, and driving habits. Safety or driver assistance features are no substitute for the driver’s responsibility to operate the vehicle in a safe manner. Financing and pre-approval are subject to credit approval. Contact Bob Howard Buick GMC for complete details regarding current vehicle inventory, pricing, and equipment.