How to Save Gas
To save on gas, drive at a steady speed and avoid tailgating, which uses up more fuel because you're hitting the gas regularly. You should also avoid idling your car, which uses gas unnecessarily. When you accelerate, pick up speed slowly so you're using as little gas as possible to get your car to its cruising speed. Additionally, turn off your climate control and all electronics before cutting the engine, since it takes more gas to turn everything back on at the same time.
Drive at the speed limit. This is the single most effective and easiest solution to increasing gas efficiency. The most fuel-efficient speed may be the point at which your vehicle shifts to high gear. For most vehicles, this is somewhere around 50 mph (80 km/h). In fact, every 5 mph (8.0 km/h) you go over 50, you can assume you're spending an extra $.25 a gallon on gas. Your efficiency decreases significantly the faster you go. What's more, lights are often timed to the speed limit. If you go faster than necessary, you're just stopping and starting anyway – which is also bad for saving gas. Avoid tailgating and constantly hitting the brakes. You can avoid wasting fuel by not tailgating. In these instances, you'll often be pressing the gas to regain the speed lost from braking which forces you to correct your following distance by applying your brakes, causing a vicious cycle. This constant up and down uses up more fuel than just driving steadily and at a safe distance. Repeated braking simply wastes energy, converting it into unnecessary heat energy and greatly reduces the service life of your brakes. In the future most cars may be equipped with systems in which braking power will be converted into reusable energy, but it is highly unlikely that your car has this technology now unless it is a hybrid. Accelerate slowly. Every time you punch the gas to quickly accelerate after stopping you are burning extra fuel and increasing tire wear. By accelerating more slowly you are only using the fuel required to get the vehicle to the cruising speed. In short, you want to use the gas and brake pedals as little as possible. Keeping that in mind while driving will keep your gas usage to a minimum. Drive smoothly and stick to one lane. Fuel consumption increases when you allow the vehicle speed to drift lower and then compensate by accelerating back up. Maintaining a steady position on the accelerator keeps the gas flowing minimally. Allowing the car to lose speed going up hills and gain speed going down increases efficiency. And as for weaving, don't do it. It's for much the same reason – when you weave in and out of lanes, you're constantly speeding up and slowing down. Relax and stick to one lane. Avoid turning across oncoming traffic. If your route will allow it, try to make as few left turns as possible on the way to your destination (or right turns in countries with left-hand traffic). Stopping and waiting at an intersection to make a turn across the oncoming lane lets the engine run idle, which wastes gas, as does accelerating once again to make the turn. Use overdrive and cruise control on the highway. Another way to keep your foot off the brakes and the gas pedal is to use overdrive and cruise control on the highway. Overdrive keeps your engine's speed down, extending the life of your engine, too. Cruise control keeps your car going at a steady rate, allowing the gas a break from pumping too hard or not pumping enough. However, it's only useful in stretches – don't bother using it in town, you'll be stopping and starting too much for it to make any difference. Use gears wisely. Higher gears at low speed and vice versa will lead to lose of more fuel. Shift gears carefully and according to the desired speed. This will cause less strain on your engine. Drive until your tank is close to empty. This part is just science: a lighter car uses less gas. What can make your car lighter? Not having a full tank. So when you hit that 1/3 of a tank and are tempted to fill up, give it a couple days. That last 1/3 of a tank may last you a bit longer than the first third did. That being said, it's generally true that gas prices spike up on the weekends, starting on Thursday afternoons. So if you think you'll need gas on Saturday, it might be wise to fill up now. Scope out any especially good gas prices to see if it's worth buying now. Avoid excessive idling. If you idle your car for more than a minute, it will save gas to turn off the engine. Also, new cars do not need to be "warmed up" on a cold winter day – a couple of seconds should do the trick. Whenever you're waiting for someone, turn off the idle. Drive thru or going inside? Going inside. You can still play the radio without idling! Turn the gas nozzle upside-down when you're done filling up. The gas nozzle is just connected to a regular hose. When you turn the hose off, there's still all that gas in the line. To get that last 1/2 cup of gas (that's 4 ounces of free gas!), turn the nozzle upside-down and give it a shake before you take it out of your tank. Lift up the hose a bit to get the gas resting in the line. Gravity causes the gas to lie at the lowest point, so lifting it up gets it out of there and into your tank. Avoid rolling down your windows at high speeds, or using the air conditioning at all. The better cooling method at freeway speeds depends on your car. Rolling down the windows creates drag, and using the air conditioning causes your engine to work harder. However, rolling down the windows is okay in city traffic. Park in the shade. More science! The cooler your car is, the less gas will evaporate from your tank. That's like giving money to the sky. And did we mention that your bum doesn't get seared on contact? It's better for your car and for you. It's hard to drive when you can't touch the steering wheel without burning yourself! Try to avoid traffic and bad weather. Fuel economy is worse in busy, high-traffic times or when it is raining, windy or when barometric pressure is high. Rain, headwind and high barometric pressure create extra air drag that uses more fuel to create and maintain forward motion. However, a tailwind (a wind behind you) helps. Which direction is the wind coming from? It should come as no surprise that high-traffic times are not good for fuel efficiency. You're stopping and starting, idling, weaving, and probably taking part in just about every bad habit for your fuel economy. Turn all electronics and climate control off before you cut the engine. Sure, when we cut the engine, everything goes off, but what about when we start it back up? If you turn everything off, the next time you start up your car, it'll take way less gas to get everything going. You can then turn everything on one at a time, which is much easier for your car to handle. Reduce the number of times you have to drive by thinking ahead. Try to consolidate errands and appointments. Get all your errands done in one go to increase your free time, too. You can also plan your trip on certain days to avoid traffic and paying higher gas prices the next week. For example, buy non-perishable necessities (including pet food, toilet needs, dry goods, and canned groceries, etc.) in bulk so you don't have to make a special trip for a few items. Make your car lighter. Get rid of any unnecessary weight in your car or truck, such as golf clubs or unnecessary tools and materials. Lowering the tailgate on a pickup truck actually reduces your gas mileage by reducing drag, too. If the tailgate isn't lowered, an air cushion is created behind the cab that creates a low drag surface for the air to travel over. But if you have to carry something, carry it in your trunk, not on the rack on top of your car. With something on top of your car, there is way more drag, slowing your car down, making it more difficult to accelerate. Change your air filter. A dirty air filter will rob the engine of power and efficiency. It will use more gas than a clean filter. So if it's been a while, get it changed. It should only take a few minutes – in fact, you may be able to do it yourself. In the scheme of car parts to replace, air filters are pretty cheap. Most are about $30-40. Keep your tires inflated to the proper pressure. Properly inflated tires will increase your traveling distance on a tank of gas. Keep a tire gauge handy and check the pressure. Tires naturally lose air over time, so don't be alarmed if one or more is low. Check your tire pressure more often when the outside temperature changes greatly. Hot tires will have high pressure from expanding air – but if air is let out to the proper amount of pressure, then when cooled they will become too low in the cooler conditions, so you'll need to reinflate them when cooler. Under inflated and greatly over-sized tires have more rolling resistance and this will reduce your miles per gallon (MPG) and cause tire wear from the excessive friction. If you do need new tires, get radial ones. They have a low rolling resistance, keeping your car aerodynamic. Keep your car tuned-up at manufacturer recommended intervals to optimize your miles per gallon. It's a good idea for your fuel economy to change spark plugs and wires on schedule, and the coil(s) when their effectiveness is breaking down (such as shorting internally). The better your engine runs, the more power it will produce using less fuel. Use synthetic oil in your car to save on fuel consumption. As a bonus, fewer oil changes are needed saving your time and reducing trips to the mechanic as well as less used oil for the environment. When you're getting your tune up, ask your mechanic about what oil you should be using for your car and for saving gas. He may be able to throw in a bottle or two with your tune-up. Use stock tires. Before changing your tires to the modern style thick ones, think again. The more the width, the higher the rolling resistance offered and higher the fuel consumption. 
Drive at the speed limit. Avoid tailgating and constantly hitting the brakes. Accelerate slowly. Drive smoothly and stick to one lane. Avoid turning across oncoming traffic. Use overdrive and cruise control on the highway. Use gears wisely. Drive until your tank is close to empty. Avoid excessive idling. Turn the gas nozzle upside-down when you're done filling up. Avoid rolling down your windows at high speeds, or using the air conditioning at all. Park in the shade. Try to avoid traffic and bad weather. Turn all electronics and climate control off before you cut the engine. Reduce the number of times you have to drive by thinking ahead. Make your car lighter. Change your air filter. Keep your tires inflated to the proper pressure. Keep your car tuned-up at manufacturer recommended intervals to optimize your miles per gallon. Use synthetic oil in your car to save on fuel consumption. Use stock tires. 