Last updated June 2026
When fuel prices surge, gas-saving tricks are as plentiful as people complaining about the high cost of filling their tanks. But automotive experts warn many of these hacks don’t work—and some could harm your car. Here’s what to do—and what not to do—to improve your mileage.
Myth #1: Premium Gas Is Better for Every Car
For most vehicle models, paying more for premium (high-octane) fuel won’t improve performance or mileage. Filling up with premium also won’t clean your engine or reduce emissions better than regular gas. Premium fuel is required only if your vehicle has a high-compression engine and your owner’s manual specifically calls for a higher minimum octane level. Otherwise, splurging on premium provides zero benefits.
Myth #2: Filling Up in the Morning Yields More Gas
The logic behind this myth: Cooler morning temperatures make gas colder and therefore less dense, so if you fill up early in the day, you’ll get more volume for your dollar. But gas station storage tanks are located deep underground, where temperatures remain constant regardless of the weather, so the time of your fill-ups is irrelevant.
Myth #3: Fuel Additives Boost Mileage
Several manufacturers sell “magic” gas-tank additives they claim will dramatically increase your miles per gallon. But testing by consumer groups and the EPA show that these products don’t work; using some of them might void your car’s warranty.
On the other hand, pumping “Top Tier” gasoline sold by dozens of major gas station brands might provide a small performance boost. A recent study by AAA found that this type of gas costs about three cents more per gallon, but it helps reduce carbon buildup on intake valves.
Many manufacturers—including Audi, BMW, Ford, General Motors, Honda, Mercedes-Benz, Stellantis, Toyota, and Volkswagen—now recommend Top Tier fuel. But using it won’t noticeably impact your miles-per-gallon.
Myth #4: Coasting or Idling in Neutral Saves Gas
Shifting your car into neutral when driving downhill or stopping at a traffic light will not save any fuel. Modern vehicles equipped with fuel injectors actually use more fuel when cars are coasting in neutral than when in gear.
Myth #5: Gas from Cheaper Stations Damages Engines
As mentioned above, there’s some evidence that “Top Tier” fuels might provide some benefits to your engine but the gas formulations sold by off-brand stations will not harm your vehicle. By law, all retail gasoline must meet the same minimum governmental standards, so if a station sells gas for less than other fill-up spots in the area you might as well grab the savings.
What Actually Saves Gas
Instead of falling for myths, here’s how you can save fuel:
- Accelerate and brake conservatively: Rapid acceleration and sudden braking are big-time gas guzzlers. For highway driving, you might benefit from using cruise control to maintain a steady pace.
- Slow down: Your vehicle will use far more fuel—as much as 30 percent more—at 75 mph vs. 55 mph.
- Lighten the load: Remove unnecessary heavy items from your trunk.
- Remove roof and bike racks: These features create wind resistance (drag), especially at highway speeds.
- Maintain ideal tire pressures: Under-inflated tires significantly lower your gas mileage.
- Keep your car properly maintained: Dirty fuel injectors cause incomplete combustion, lowering fuel economy. A faulty oxygen sensor can decrease fuel efficiency by as much as 40 percent.
- Turn off the AC if you don’t need it: ACs gobble up your vehicle’s resources and can cost you up to four miles per gallon.
- Comparison shop: Prices can vary greatly in the same region. You may find the lowest prices at warehouse stores (Costco, Sam’s Club), or supermarkets that sell fuel. Supermarket points can lower the posted price by as much as a dollar a gallon. Fuel apps, such as Gas Buddy, provide real-time price comparisons.
- Switch to a more efficient vehicle: Some hybrids burn half as much gas as their non-hybrid counterparts. In many parts of the U.S., it costs significantly less to power an electric vehicle than a car with an internal combustion engine.
Contributing editor Herb Weisbaum (“The ConsumerMan”) is an Emmy award-winning broadcaster and one of America's top consumer experts. He has been protecting consumers for more than 40 years, having covered the consumer beat for CBS News, The Today Show, and NBCNews.com. You can also find him on Facebook, Blue Sky, X, Instagram, and at ConsumerMan.com.