How to Get Better Gas Mileage: Tips That Actually Work for San Antonio Drivers

Gas prices in San Antonio can swing fast, and even a few cents per gallon adds up quickly when you’re commuting on I-35 or running errands across the city. The good news is that a lot of the things that hurt your fuel economy are easy to fix. You don’t need a new car. You just need to know where the waste is happening.

Here’s a straightforward look at how to get better gas mileage, covering everything from your driving habits to a few simple maintenance items most people overlook.

Which Driving Habits Are Killing Your Fuel Economy?

This is where most of the damage happens. Your driving habits have a bigger impact on gas mileage than almost anything else, and a few adjustments behind the wheel can improve your MPG noticeably.

Rapid Acceleration and Hard Braking

Flooring it off the line at a red light on Loop 1604 and then slamming the brakes at the next one is one of the fastest ways to burn through fuel. Rapid acceleration forces your engine to work much harder than it needs to. Smooth, gradual starts use significantly less gas and are easier on your brakes too.

Idling Longer Than You Need To

Idling gets zero miles per gallon. If you’re sitting in a drive-through on San Pedro Ave for more than a minute or two, or warming up your car in the driveway on a cool morning longer than 30 seconds, you’re burning fuel for nothing. Modern engines don’t need extended warm-up time. The engine warms up faster when you drive gently.

Highway Speeds and Wind Resistance

Fuel efficiency drops fast once you push past 60 mph. At higher highway speeds, aerodynamic drag increases significantly, and your engine has to work much harder to push the vehicle through the air. According to the U.S. Department of Energy, every 5 mph you drive over 50 mph is roughly equivalent to paying an extra $0.18 to $0.30 per gallon. Keeping it at 65 instead of 75 on US-90 makes a real difference over time.

Use Cruise Control on the Highway

When you use cruise control on a flat stretch of highway, your speed stays consistent. That consistency saves fuel because your engine isn’t constantly adjusting to small variations in your foot pressure. Stop-and-go traffic on city streets is different. Cruise control doesn’t help there. But on a long straight run from San Antonio toward New Braunfels, it’s worth switching on.

What Maintenance Items Affect Fuel Efficiency?

A poorly maintained vehicle burns more fuel. These are the items most worth staying on top of if you want to improve fuel economy.

Tire Pressure

This one is easy to overlook. When your tires are underinflated, there’s more rolling resistance between the tire and the road, which means your engine works harder to move the vehicle. 

Check your PSI at least once a month. The correct tire pressure for your vehicle is on the sticker inside the driver’s door, not on the sidewall of the tire itself. San Antonio summers are brutal on tire inflation levels since heat causes air to expand, so it’s worth keeping a gauge in the glove box.

Spark Plugs and Tune-Ups

Worn spark plugs cause misfires, which means your engine isn’t burning fuel as efficiently as it should. Regular tune-ups keep combustion running cleanly. 

Check your owner’s manual for the service interval. Most modern vehicles recommend spark plug replacement somewhere between 60,000 and 100,000 miles, but it varies by make and model. Remember to get OEM part replacements from one of Northside Auto Group’s Parts Centers so you don’t void your warranty.

Synthetic Motor Oil

Using the right oil matters. Synthetic motor oil reduces internal engine friction better than conventional oil, which translates to slightly better fuel efficiency. If your vehicle’s manufacturer recommends synthetic, use it. Switching to a high-quality synthetic that meets your engine’s specifications is a small cost that pays off over time.

At Northside Auto Group, our dealership’s Service Centers, factory-trained technicians can help you get a full-synthetic oil change so you can keep your engine healthy. When your engine is in better shape, you’ll save money at the pump. Schedule an oil change with us today.

Gas Cap and Fuel Tank

A loose or cracked gas cap lets fuel evaporate from your tank. It’s a small thing, but it can trigger your check engine light and slowly drain your gas without you noticing. If your gas cap doesn’t click when you close it, replace it. They’re inexpensive and available at any auto parts store.

Does the Type of Gas You Use Matter?

For most vehicles, the answer is no. If your owner’s manual says regular unleaded is fine, using premium gas won’t improve your fuel economy or your engine performance. Premium gas has a higher octane rating, which only matters for engines specifically designed to require it. Paying more for premium gas when your car doesn’t need it is just a waste of money.

That said, using Top Tier gas (look for the Top Tier logo at the pump) does make a difference. Top Tier certified fuels contain higher levels of detergent additives that help keep fuel injectors and intake valves clean. Over time, cleaner fuel delivery means better combustion and better efficiency.

How Does What You Carry Affect Your MPG?

Weight and aerodynamic drag both eat into your fuel economy. Here’s what to watch:

• Roof racks and cargo boxes: An empty roof rack adds aerodynamic drag even when you’re not carrying anything. If you’re not using it, take it off. A cargo box up top can drop your highway MPG by 10-25% depending on your vehicle and speed.
• Unnecessary weight in the vehicle: That bag of mulch you’ve been meaning to unload, the toolbox rattling in the back. Every extra 100 pounds reduces fuel economy by about 1%. It’s not a huge number on its own, but it adds up.
• Air conditioning: Using A/C increases fuel consumption, especially at lower speeds. In San Antonio summers that’s unavoidable for most people, but at highway speeds the drag from open windows is actually worse than running the A/C. Use your judgment.

Should You Consider an EV to Improve Fuel Economy?

EVs don’t use gasoline at all, so the fuel economy conversation shifts to electricity costs and charging habits. For San Antonio drivers who do most of their driving in the city, an EV can significantly cut fuel costs. The Northside Auto Group carries several EV options, and the team at thenorthsideautogroup.com can walk you through what makes sense for your commute and budget.

If you’re not ready to go fully electric, hybrid vehicles offer a real middle ground. They recover energy through regenerative braking, which is especially useful in stop-and-go traffic on San Antonio city streets.

Frequently Asked Questions About Gas Mileage

How much does tire pressure affect gas mileage?

Underinflated tires can lower your MPG by 0.2% for every 1 PSI drop below the recommended level. Multiply that across all four tires and you can lose 1-3% of your fuel efficiency just from low tire inflation alone. It’s one of the easiest fixes on this list.

Does idling waste a lot of gas?

Yes. Idling burns roughly a quarter to half a gallon of fuel per hour depending on engine size. If you’re stuck in a long drive-through or waiting to pick someone up, shutting off the engine saves more gas than you might think.

Does premium gas improve fuel economy?

Only if your vehicle requires it. If your owner’s manual says “premium recommended” or “premium required,” then yes, using the right octane matters. If your car runs fine on regular, paying more for a higher octane rating won’t give you better gas mileage.

How much does a roof rack hurt fuel economy?

More than most people expect. Even an empty roof rack adds wind resistance. Studies show roof racks can reduce highway fuel economy by 6-17%, and a fully loaded cargo box can push that number to 25% or more. Remove it when you’re not using it.

Do air filters affect gas mileage?

A clogged air filter restricts airflow to the engine, which affects how efficiently it burns fuel. Replacing a dirty air filter is a quick, inexpensive fix that helps your engine breathe properly. Check yours every 15,000-30,000 miles or whenever you have your oil changed.

What’s the single biggest thing I can do to improve fuel economy?

Change how you accelerate. Smooth, gradual acceleration instead of rapid starts has a bigger impact on real-world fuel economy than almost any other single change. Combine that with keeping your tires properly inflated and you’ll notice a difference at the pump.

Looking for a More Fuel-Efficient Vehicle in San Antonio?

If you’ve optimized your driving habits and maintenance routine and you’re still not happy with your fuel economy, it might be time to look at a newer, more efficient model. Northside Auto Group carries fuel-efficient options across Ford, Chevrolet, and Honda, including hybrids and EVs. Browse our new vehicle inventory or stop by San Pedro Ave to talk through your options with our team.