Ownership & Service › Fuel Economy Five Ways to Improve Your Car's Fuel Economy in Jacksonville, FL By Stephen Aten, eCommerce Director, Tom Bush Family of Dealerships | August 26, 2026 Fuel economy is won on ordinary Jacksonville commutes, not on road trips. Quick Answer The five most effective ways to improve your car's fuel economy are keeping tires properly inflated, driving smoothly, holding a steady highway speed, removing unnecessary weight, and staying current on manufacturer-recommended maintenance. U.S. Department of Energy data shows these habits can recover 10% to 40% of the fuel wasted by aggressive driving alone. In This Guide 1. Keep Your Tires Properly Inflated 2. Drive Smoothly 3. Maintain a Steady Speed 4. Remove Unnecessary Weight 5. Keep Up With Regular Maintenance The Florida Factor: Heat and Air Conditioning Your 10-Minute Fuel Economy Checklist Frequently Asked Questions Fuel prices move constantly, and there is nothing you can do about that. What you can control is how much fuel your vehicle actually uses to get you from Arlington to downtown, from Orange Park up I-295, or out to the beach on a Saturday. Improving your car's fuel economy is not about buying anything. It is about five habits, most of which cost nothing and take a few minutes. Here is our position, and it is a slightly unpopular one: the single biggest fuel economy variable in Jacksonville is not your engine, your tires, or your fuel grade. It is your right foot. The U.S. Department of Energy puts the cost of aggressive driving at 15% to 30% of your gas mileage at highway speeds and as much as 40% in stop-and-go traffic. No maintenance item on this list comes close to that number. The mechanical tips below matter, and we will get to all of them, but they are the smaller half of the equation. We will also correct one piece of advice you have almost certainly been given, because it is not true for the vehicle in your driveway. Take your time with this one. There is nothing here that needs to be done today. 0.2% MPG lost per 1 psi of tire pressure Source: U.S. DOE 10–40% MPG lost to aggressive driving in traffic Source: U.S. DOE 25%+ MPG lost to A/C on short trips in heat Source: U.S. DOE 1. Keep Your Tires Properly Inflated Quick Answer Properly inflated tires improve gas mileage by 0.6% on average and up to 3% in some cases, because under-inflated tires lower gas mileage by roughly 0.2% for every 1 psi the average pressure drops. Use the psi figure on the driver's door jamb sticker, not the number molded into the tire sidewall. Check pressure when tires are cold — before driving, not after. An under-inflated tire has a larger contact patch and flexes more as it rolls. That flex creates rolling resistance, and your engine burns extra fuel overcoming it. It also wears the shoulders of the tire prematurely, which is the more expensive half of the problem. Two things worth knowing. First, the correct pressure is on the sticker inside your driver's door jamb, not the raised number on the tire itself — that sidewall figure is the tire's maximum, not your vehicle's target. Second, your tire pressure monitoring system is not an early warning. Most systems only alert at roughly 25% below the recommended pressure, by which point you have already been losing fuel economy for weeks. Check them cold, once a month, with a $12 gauge. It is five minutes in your driveway. If you would rather not, any of our service departments across the Tom Bush family of stores will check and set them at no charge while you wait. 2. Drive Smoothly Quick Answer Aggressive driving — speeding, hard acceleration, and sudden braking — lowers gas mileage by roughly 15% to 30% at highway speeds and 10% to 40% in stop-and-go traffic, according to the U.S. Department of Energy. Accelerating gradually and anticipating traffic is the single largest fuel economy improvement available to most drivers. Every hard brake is fuel you already paid for, converted to heat. Every time you brake hard, you are throwing away momentum your engine burned fuel to create. Every time you accelerate hard to close a gap, you buy it back at a premium. Do that thirty times on a commute down Atlantic Boulevard and the cost is real. The habit that fixes it is not driving slowly — it is looking further ahead. Watch two or three cars up instead of one. Read the light cycle before you get to it. Leave enough following distance that a car merging in front of you costs you a small lift off the throttle instead of a hard brake. Drivers who do this arrive at the same time as everyone else, because in city traffic your average speed is set by the lights, not by your acceleration. The Bottom Line If you only change one thing after reading this, change how you approach a red light. Coasting toward a light you can already see is red uses almost no fuel. Accelerating toward it and braking hard uses the most fuel of anything you do in a car. 3. Maintain a Steady Speed Quick Answer Gas mileage usually decreases rapidly above 50 mph, and each 5 mph driven over 50 mph can lower gas mileage by 7% or more, according to the U.S. Department of Energy. On highway stretches of I-95 or I-295, holding one steady speed uses measurably less fuel than repeatedly speeding up and slowing down. Above 50 mph, aerodynamic drag becomes the dominant fuel cost. There are two separate effects at work here, and it helps to keep them apart. The first is drag: air resistance rises with the square of your speed, so the faster you go, the more of your fuel is spent pushing air out of the way. The second is variation: constantly speeding up and slowing down costs fuel on top of whatever your average speed already costs you. On the open stretches of I-95 south toward St. Augustine or I-295 through Mandarin, cruise control is a genuine fuel economy tool because it holds speed better than your foot does. In heavy commuter traffic it is less useful, and around Nassau County's rolling grades it can actually work against you by aggressively downshifting to hold speed up a hill. Use it where the road is flat and the traffic is thin. Habit Estimated fuel economy impact Source Aggressive driving in traffic −10% to −40% U.S. DOE Each 5 mph over 50 mph −7% or more U.S. DOE A/C on short trips in extreme heat −25% or more U.S. DOE Roof-top cargo box −2% to −17% U.S. DOE Every extra 100 lbs carried −1% U.S. DOE Every 1 psi of tire pressure lost −0.2% U.S. DOE Wrong grade of motor oil −1% to −2% U.S. DOE Fixing an out-of-tune engine +4% average U.S. DOE 4. Remove Unnecessary Weight Quick Answer An extra 100 pounds of cargo lowers gas mileage by about 1%, according to the U.S. Department of Energy. Roof-mounted cargo is far more costly than weight in the trunk: a roof-top cargo box can reduce fuel economy by 2% to 17% because it adds aerodynamic drag on top of the added weight. Weight in the trunk costs about 1% per 100 lbs. Weight on the roof costs far more. Weight in the cabin or trunk is the smaller of the two issues. A hundred pounds of gear you have been meaning to unload costs you roughly 1%. Worth fixing, but not dramatic. Roof cargo is the one people underestimate. A cargo box, kayak rack, or bike carrier does not just add pounds — it adds a wall of aerodynamic drag exactly where your vehicle was shaped to be smooth, and drag scales with speed. That is why the penalty range runs all the way to 17%. If you carry boards to the beach or a box to the mountains a few weekends a year, take the rack off between trips. It is a ten-minute job that pays every day you drive. 5. Keep Up With Regular Maintenance Quick Answer Fixing an out-of-tune engine improves efficiency by about 4% on average, and using the wrong grade of motor oil lowers gas mileage by 1% to 2%, according to the U.S. Department of Energy. Following your manufacturer's maintenance schedule protects the fuel economy your vehicle was engineered to deliver. Fixed right the first time — factory-trained technicians, brand-approved parts. Maintenance does not usually make a healthy car more efficient than it was designed to be. What it does is stop a car from quietly getting worse, and recover mileage a car has already lost. Those are both worth money, but they are different claims, and dealers are not always careful about the difference. The two items with the clearest evidence behind them are motor oil grade and engine condition. Using a heavier grade than your manufacturer specifies costs 1% to 2%, which is why the grade printed on your oil cap is a specification and not a suggestion. And a vehicle running out of tune — a failing sensor, a misfire you have learned to ignore — recovers about 4% on average once it is repaired. The tip we need to correct Now the unpopular part. You have probably been told that replacing a clogged engine air filter improves your gas mileage. On a modern fuel-injected vehicle, the U.S. Department of Energy says plainly that it does not. Your engine computer compensates for restricted airflow, so the fuel economy stays roughly where it was. That guidance held true for older carbureted engines, and it has been repeated ever since. A clean air filter still belongs on your maintenance schedule — it improves acceleration and protects the engine from ingesting debris, and in Northeast Florida's pollen and coastal dust it earns its keep. It is simply not a fuel economy fix, and we would rather tell you that than sell it to you as one. From the Tom Bush Service Drive “Across our six Jacksonville stores, the fuel economy complaints that turn out to have a real mechanical cause are usually one of three things: tires that have been low for months, a check-engine light the owner learned to live with, or the wrong oil from a quick-lube shop. All three are cheap to find and cheap to fix. We would rather tell you it is your tires than sell you a service you do not need.” Stephen Aten, eCommerce Director, Tom Bush Family of Dealerships The Florida Factor: Heat and Air Conditioning Quick Answer Air conditioning use can reduce a conventional vehicle's fuel economy by more than 25%, and the effect is largest on short trips in very hot weather, according to the U.S. Department of Energy. For Jacksonville drivers between May and September, A/C is often a bigger fuel economy variable than tire pressure and cargo weight combined. Parking in shade lowers cabin temperature and shortens the A/C's hardest working minutes. Every national fuel economy list is written for a national climate. Ours is not one. From roughly May through September, the largest single draw on your fuel economy in Jacksonville may be the air conditioning — more than 25% on short trips in extreme heat, which is a bigger number than most of the tips above. We are not going to tell you to drive without air conditioning in a Jacksonville August. That is not advice, it is an endurance test. The realistic version is this: the A/C works hardest during the first few minutes, pulling a 140-degree cabin down to something livable. So the fix is fewer cold starts, not less cooling. Combine errands into one trip. Park in shade or use a windshield shade. Crack the windows for the first thirty seconds to dump the hottest air before the compressor has to. And on a highway run, keep the windows up — above about 45 mph, open windows cost more in drag than the A/C costs in load. Your 10-Minute Fuel Economy Checklist Take This With You The Saturday Morning Fuel Economy Check Everything here can be done in your driveway, before the car has been driven, with no tools beyond a tire gauge. Work down the list once a month. ✓ Find the psi figure on your driver's door jamb sticker — not the tire sidewall ✓ Check all four tires cold, before driving, and set them to that figure ✓ Check the spare too, if your vehicle carries a full-size one ✓ Empty the trunk and cabin of anything you are not actively using ✓ Remove the roof rack, cargo box, or bike carrier if the next trip is weeks away ✓ Confirm the oil grade on your last service receipt matches your oil cap ✓ Note any check-engine light or rough idle and schedule it — that is the 4% item ✓ Look up your next scheduled service interval and put it on the calendar ✓ Pick one route you drive daily and plan where you will coast instead of brake Schedule Service at Your Tom Bush Store → Frequently Asked Questions What is the fastest way to improve my car's fuel economy? Checking and correcting your tire pressure is the fastest improvement available to most drivers, and it takes about five minutes. The U.S. Department of Energy reports that properly inflated tires improve gas mileage by 0.6% on average and up to 3% in some cases, because under-inflated tires lower gas mileage by roughly 0.2% for every 1 psi the average pressure drops. Does replacing my engine air filter improve gas mileage? Not on a modern vehicle. The U.S. Department of Energy states that replacing a clogged air filter does not improve fuel economy on newer fuel-injected engines, because the onboard computer compensates for restricted airflow. A clean air filter still matters for acceleration and engine protection, so it belongs on your maintenance schedule. It just is not a fuel economy fix. How much does running the air conditioning hurt fuel economy in Florida? Air conditioning use can reduce a conventional vehicle's fuel economy by more than 25%, and the effect is largest on short trips in very hot weather, according to the U.S. Department of Energy. That makes it one of the biggest fuel economy variables for Jacksonville drivers from roughly May through September. The practical answer is not to suffer without air conditioning, but to combine errands so the cabin is cooled once instead of four separate times. Does driving slower on I-95 actually save fuel? Yes. Gas mileage usually drops rapidly above 50 mph, and the U.S. Department of Energy estimates that each 5 mph driven over 50 mph can lower gas mileage by 7% or more. On a highway commute between downtown Jacksonville and Ponte Vedra or St. Johns, easing off by 5 mph and holding a steady speed is a measurable savings, not a rounding error. How much fuel does extra weight in my trunk cost me? About 1% of your gas mileage per extra 100 pounds, according to the U.S. Department of Energy. Roof-mounted cargo is a much larger penalty because it adds aerodynamic drag rather than just weight: a roof-top cargo box can reduce fuel economy anywhere from 2% to 17%. If you only use a cargo box for trips to the Smokies or Georgia, take it off when you get home. Will regular service at a dealership improve my fuel economy? It protects the fuel economy the vehicle was built to deliver, and it can recover mileage you have already lost. The U.S. Department of Energy reports that fixing an out-of-tune engine improves efficiency by about 4% on average, and that using the wrong grade of motor oil lowers gas mileage by 1% to 2%. Both are exactly the kind of thing a factory-trained technician catches during a scheduled service visit. Common Questions, Answered in One Line Where do I find the correct tire pressure for my car? On the sticker inside the driver's door jamb — the number on the tire sidewall is the tire's maximum, not your vehicle's target. How often should I check tire pressure? Once a month, and always when tires are cold, before the car has been driven. Will my TPMS warning light tell me before I lose fuel economy? No — most systems only alert at roughly 25% below recommended pressure, long after fuel economy has started slipping. Is premium fuel better for fuel economy? Only if your manufacturer requires it; in an engine designed for regular, premium fuel does not improve mileage. Does idling in a drive-thru waste much fuel? Idling uses roughly a quarter to a half gallon of fuel per hour, per the U.S. Department of Energy. Windows down or A/C on? Windows down in slow city traffic, A/C on above roughly 45 mph where aerodynamic drag outweighs the compressor load. Does cruise control always save fuel? On flat, open highway yes; in heavy traffic or on rolling hills it can work against you. Do I need to warm up my car before driving? Not in Florida — modern engines warm fastest under gentle driving, and extended idling only burns fuel. How much does a roof rack cost me if I leave it on year-round? Up to 17% of your fuel economy, which is why it is worth removing between trips. Can Tom Bush check my tire pressure without an appointment? Yes — stop by any of our Jacksonville-area service departments and we will check and set them at no charge. Six Stores. One Standard. Factory-trained technicians and brand-approved parts across the Tom Bush Family of Dealerships. Family-owned in Jacksonville since 1970. No pressure, and no service you do not need. Schedule Service → Find Your Store Shopping for something more efficient? Browse new and pre-owned inventory across all six Tom Bush stores → | Need tires? See our tire and parts department → About the Author Stephen Aten eCommerce Director — Tom Bush Family of Dealerships Stephen Aten leads digital strategy across the six Tom Bush rooftops in Jacksonville and Orange Park, working daily with the group's sales and service teams. The Bush family has served Northeast Florida since 1970, and is now in its fourth generation of family ownership. Sources 1. Keeping Your Vehicle in Shape — U.S. Department of Energy & U.S. EPA 2. Driving More Efficiently — U.S. Department of Energy & U.S. EPA 3. Fuel Economy in Hot Weather — U.S. Department of Energy & U.S. EPA 4. Fuel Economy Tips — U.S. Department of Energy & U.S. EPA