The easiest step to driving more fuel efficiently is to make your car as efficient as possible. One simple step that usually only costs about $50 is to replace your crappy paper air filter in the engine’s air intake with a cotton, high flow K&N one. They make one for basically any vehicle and you can get them at most auto parts stores. Typically they let about 50% more air into the engine. Now your air flow and temperature sensor and fuel injection system are supposed to work together to only send in enough fuel for the amount of oxygen in the amount of air passed in through the intake. But it never works quite as perfectly as that sounds and adding 50% more air makes the fuel burn more completely, giving you more energy from each engine cycle. This alone added 1-2 MPG highway in my Mercury Cougar. This is not nearly as effective in all cars as other modifications though.
Another fantastic idea that isn’t terribly expensive is to switch over to full synthetic oil. I personally have done that in 2 vehicles and gotten an extra 1-2 MPG. Of course this particular upgrade usually only really helps vehicles with over 30,000 miles and only if they’re getting under the factory MPG rating. But during the 2nd half of the recommended 1500 miles between oil changes, synthetic oil hasn’t burned off nearly as much as conventional so it keeps the engine lubricated better which results in less friction and less power lost every time the pistons go up and down. So instead of starting with 28MPG and ending with 25 3000 miles later, you’ll start with 28 and end with 27 MPG because far less oil molecules broke down.
Next, you need to make your vehicle as light as possible. When a 200 pound person is sitting in the passenger seat, you usually lose at least 1 MPG if not 2. So obviously if you ride alone AND lighten your car by 200 pounds, you’ll gain about the same amount. Unfortunately, that’s hard to do. Some drastic steps include replacing your hood with a fiberglass or carbon fiber one that weighs a lot less and taking out the passenger seat completely. If it’s not a powered seat, usually you just take off the 4 bolts and pull it out. Seats usually weigh at least 50 pounds so if you drive to work every day without someone sitting in the passenger seat, you should probably remove it. My favorite suggestion is to take out the scissors jack and spare tire in your trunk. That’s about 40 pounds you don’t need. Of course you’ll probably want to put a can of flat tire fixer in its place. Any useless junk you have in your trunk or back seat needs to go too. I know some people who had 50 pounds of clothes and shoes and bags and electronics and stuff in their trunk. It’s time to clean it out! This probably isn’t legal and definitely isn’t safe but you can cut off the steel frame that makes up the actual structural part of your bumper to lose like a hundred pounds. In the winter you can disconnect and remove your air conditioning compressor which also weighs a lot but that can throw some check engine light codes.
Next is the electrical system. Your alternator creates electricity to power everything in your car and it’s connected to the belt on the engine that drives everything else. So when it senses that more electricity is needed, it effectively adds more resistance to the engine which requires you to use more gas to maintain the same speed. Try holding your foot perfectly still on the gas pedal on the highway with cruise off. Then turn on the rear defrosters. You’ll slow down about 2-3 MPH. So to cut down on electrical usage, don’t turn on anything electrical in your car unless you really need it. People that drive with their headlights on at noon are idiots and it’s killing their gas mileage.
Another item that takes power from the engine’s main belt is the air conditioning. It is not always more efficient to just open the front windows. That will create a huge amount of drag or wind resistance that will slow your car down. For the average car, if you’re going under 45 MPH, opening the windows will result in the best gas mileage. At over 45 MPH, opening the windows will get you worse gas mileage than running the AC. Also, turning your car on regular AC instead of max AC is far less efficient in many cars. In most Ford cars at least, max AC simply means it will run the compressor a little more and recycle the air in your car and feed it back into the AC system instead of trying to cool down outside air. If your car is like that, always use max AC except when your car has been sitting outside in the sun and it’s like 140 inside your car and 80 outside. Then use regular AC until it cools down and switch to max later.
Next make sure your tires are all the same pressure and all the proper pressure. Don’t look on the side of the tire for the recommended PSI because that’s the maximum recommended pressure, not the pressure your specific car should be driving at. Look up your car’s recommended pressure online, in the owner’s manual, or on the sticker on the skinny, inside edge of the door or the door well. Then add two PSI to it because those ratings are optimized for ride comfort, not gas mileage. Then use an accurate gauge to fill them all up equally. It’s worth the 3 dollars to get a decent pressure gauge. Driving under inflated tires can drop your gas mileage by 2 or more MPG. It also wears out your tires at least 10x faster on turns.
Speaking of tires, if you’re about to buy some new ones try to find out what the rolling friction rating is on them. That’s the amount of energy lost to friction simply by moving. If you’re on a flat surface and go 25 MPH then put the car in nuetral and glide, low rolling friction tires will get you a lot farther before you stop. This results in better gas mileage in real driving situations.
Now it’s time to learn how to drive more efficiently. When it’s safe and proper to do so, glide as far as you can with your foot off the gas pedal and off the brake before stopping. Like on the highway offramp for example, instead of staying on the gas half way down then braking, glide down without any gas and brake slowly. Every time you press the brakes, you throw away the energy it took to get going as fast as you were and it drops your gas mileage. So if you glide down the offramp, you’re using as much energy as you can from when you got on the highway in the first place. Also if you see a light five hundred feet ahead of you turn red, immediately take your foot off the gas and glide up to it slowly so you don’t waste gas to get there faster when you’re only going to sit idle anyway.
Some other good driving techniques are to avoid running your engine if you’re not moving. Don’t warm your engine up in winter for 3 minutes before getting in it, because your gas mileage while not moving is 0 MPG. You’re basically just burning off gasoline. And don’t start your car then buckle up then put your bags in the back then put on your makeup then unwrap your sandwich and start eating it. Only start your car when you’re actually ready to drive. You should start it then a second or two later, be shifting into drive or reverse and going somewhere. Doing so will save more gas than you might think. Also, don’t rev your engine too high to get going from a stop. Keep it under 2000 RPM whenever possible. Also, fill up your tank around when it’s a bit under 1/8 full. Any less gas and your fuel pump may not deliver enough fuel to run efficiently. And if you’re one of those crazy people that always fills up at half, you’re carrying around an extra bunch of pounds of fuel all the time which is pointless.
One final driving tip is drafting. Get as close to tall, wide vehicles on the highway as possible without being unsafe. Since your braking distance is at least 4x shorter than a semi, if they slam on their brakes, you’re not going to hit them as long as you react fast enough. Once you feel your car shake slightly back and forth, you know you’re close enough. That’s the wind swirling around in vortexes along the back side of the vehicle you’re behind. It’s an extremely low pressure area with very little wind resistance. According to my real world tests, I went from 30MPG to 37MPG by drafting behind a semi.