How to Increase Fuel Mileage on a Car

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As gas prices continue to climb, increasing the fuel mileage is the best way to protect your pocket book. Here are a few ways to spend less money on gas by increasing your car's efficiency in using it.

Steps

1. Plan your trips. Keep lists of needs that will require a trip and try to accomplish multiple objectives with each. This will not increase your fuel mileage (the number of miles your car moves for each gallon of gas), but it will help you drive less (which, in turn, means you use less gas).
2. Lighten your load. Get the lightest car that will serve your needs. Weight is one of the biggest causes for loss of kinetic energy in non hybrid cars. If you're not shopping for cars, then take any extra weight off of the one you're already driving. If seats that you don't use can be removed, take them out. If you use your trunk as a storage space for heavy things, find another place for them. An extra 100 pounds increases fuel consumption by 1-2%. (Weight is most important in stop-and-go driving. In almost exclusively highway driving, it matters little: once the car is up to speed, it need only push air out of the way.) Don't remove things from the car that you need frequently; instead, make sure these are in the car and readily accessible because wasted trips to retrieve or replace them will be much worse than a little lower mileage.
3. When you fill up with gas, fill up completely and try and keep your tank above one third full. If your fuel runs low, the engine might not receive a steady supply of gas (since it will splash around while you're driving and it might momentarily splash away from the tube that leads gas out of the tank). Not having a steady supply of gas will make your engine less efficient. The benefits of having a full tank will outweigh the drawbacks of having the added weight.
4. Slow down. The faster you move, the harder your engine has to work to push through the wind. Speeding can reduce fuel efficiency by up to 33%. (Factors other than air resistance decrease fuel economy below about 60 MPH, so fuel economy is not a reason to go slower, but fuel economy decreases rapidly above that speed).
5. Use cruise control. In most situations, using your cruise control reduces fuel consumption by maintaining a constant speed.
6. Accelerate smoothly with moderate throttle. Engines are most efficient with moderately high air flow (throttle) and at revolutions per minute (RPM)s up to their power peak (for small to mid sized engines this is generally somewhere between 4k to 5k RPM). In a manual transmission car, practice 'short shifting', or shifting to higher gears as soon as you reach your desired speed by skipping intermediate gears. For example, accelerate to 40 mph using 1st gear and 2nd gear, then shift directly to 4th (skipping 3rd), or if your engine can maintain your speed, to 5th. (Be aware that if you have to floor the accelerator pedal in 5th to maintain your speed, you should be in 4th!).
7. Plan your route carefully. Take the route with the fewest stops and turns and least traffic. Take highways in preference to city streets when possible.
8. Avoid braking wherever possible. Braking wastes energy from fuel that you have already burned, and accelerating after braking consumes more fuel than driving at a constant speed. On city streets watch ahead and coast when you see a red light or traffic jam ahead.
9. Set your tires to the proper inflation. Properly inflated tires can reduce fuel consumption by up to 3%. Your tires also lose about 1 PSI per month, and when the tires are cold (e.g., in the winter), their pressure will decrease due to the thermal contraction of the air. It is recommended to check tires at least monthly, preferably weekly. Having properly inflated tires will also help you avoid uneven wear on the tread. Some gas stations, such as some Sheetz's, have automatic air compressors that stop at a pre-determined level. (For safety, double-check pressure with your own gauge, especially if another is suggesting you add a surprisingly large amount of air.) Small permanently-installed valve-stem extensions can allow filling without removing the caps, but check that they are not themselves prone to jamming with foreign matter and leaking. Recommended inflation pressures are for cold tires; put about 3 PSI more in if the tires have been driven on awhile. Inflate to the pressure recommended by the car manufacturer, not the maximum stamped on the tire. (In one authors experience with cars and trucks never inflate to the pressure indicated in the manufacturer manual unless you have stock tires. Too much psi and explode the tire [expensive] and putting too little nets horrible fuel economy. Always inflate to pressure stated on sidewall.)
10. Tune up your engine. A properly tuned engine maximizes power and can greatly enhance fuel efficiency. Beware, though, that many tuners will disable efficiency measures when tuning for power.
11. Check the condition of your engine air filter. A dirty filter will reduce fuel economy, or make the engine stall when idling. Just like mowing dusty grass, driving dusty dirt roads will clog the air filter: avoid dust clouds.
12. Replace your fuel filter according to your manufacturer's recommended schedule. This will go a long way to enhancing fuel efficiency.
13. Avoid excessive idling. Idling a vehicle wastes a significant amount of fuel. The best way to warm up a vehicle is to drive it slowly until it reaches proper operating temperature.
14. Try to avoid using the air conditioner in stop and go city driving as it causes the engine to work hard and consume more fuel. However, studies show that at highway speeds cars get somewhat better mileage with the AC on and the windows rolled up. The drag caused by rolled down windows at high speed reduces fuel efficiency more than the AC.
15. Find your car's "sweet speed". Some cars get better mileage at specific speeds, usually 50 mph. Your car's "sweet speed" is the minimum speed at which the car is running in its highest gear (watch for rpm drops as you accelerate to determine when your transmission is shifting into higher gears). For example, most Jeep Cherokees are best at 55 mph, and Toyota 4Runners are best at about 50 mph. Find your vehicle's "sweet speed" and pick your roads accordingly.
16. Use synthetic oil in your car to save on average 5% gas. (It seems unlikely to one author at least that synthetic oil would cause a car to work much less hard; it is not much less viscous.) Remember to change it according to your vehicle manufacturers recommendations for any oil. Extending oil change intervals can be harmful to the life of your engine and the fuel saving benefits are lost as oil gets dirty. If you cant use synthetic, choose the lightest oil possible, 15-30 rather than 20-50.
17. When getting your oil changed, use a synthetic oil additive to either natural or synthetic oil. This can increase your gas mileage by up to 15% if you follow the manufacturer's instructions and recommended usage. (It seems unlikely to one author at least that synthetic-oil "additive" would cause a car to work much less hard; it would not make the oil overall much less viscous, and circulating the oil is only a relatively small task for a car engine.)
18. If your car has an automatic transmission with overdrive, make sure you enable overdrive except when towing very heavy trailers. Overdrive is by default enabled on the "D" on most shifters. Several cars have buttons on the shifter which allow you to turn off the overdrive gear. Don't turn it off except in specific circumstances it may be needed such as for engine braking downhill or failure to proceed uphill smoothly in overdrive. Overdrive saves you gas mileage at higher speeds by using a lower ratio from engine speed to wheel speed - this places the engine at a more efficient operating point (by reducing throttling losses, etc).
19. Learn to watch and predict traffic signals. Stop-and-go driving is wasteful.
20. Don't circle in a parking lot, and keep well away from the store fronts. Look for a spot in the empty half of the parking lot. Many people spend significant time idling and creeping, waiting for a "close spot" to open up.
21. Maintain a log over time of how many miles you go (the main odometer) and how much gas you put in (from the gas pump, including fractions). Put it in a spreadsheet. It will keep you focused, and other methods are inaccurate; you will never know for sure if you're saving fuel, wasting fuel or just seeing errors from gas pumps that stop pumping at different points, or fractions of miles being dropped off your 'trip' odometer when you reset it.
22. Maintain a safe following distance! Don't stick to the bumper of the car directly in front of you. You will brake more and accelerate more to keep that unnecessary and dangerous narrow gap. Relax. Hang back a bit. You're still traveling at the same speed as the car ahead of you even if you're 100 yards behind. This also gives you a lot more room to play with when you are timing lights. When he slams on his brakes, you can coast down and see if the light quick-changes green again (some do). You might even coast by his car as the light turns green and he has to accelerate from a dead stop.
23. Avoid idling. For example, in cold weather warm the car engine no more than 30 seconds. This period of time is sufficient to ensure that the engine is properly lubricated for driving. Generally, if you can avoid 10 seconds of idling you will save gas by turning the engine off and restarting. However, starting an engine too often can lead to excessive wear and tear on the starter motor and wiring.
24. Select the narrowest possible tires for your vehicle that will satisfy your driving style and demands. Narrow tires have less frontal area, thus reducing aerodynamic drag. Remember, however, that narrow tires have less traction as well (which is why race cars have such wide tires). Do not get a tire that is incompatible with your wheels, and do not get smaller wheels unless your manufacturer approves.
25. Select low-rolling-resistance compound tires. These can increase fuel economy by a few percent. (The difference is not startling or a substitute for proper inflation. It would be wasteful to replace the former tires with these before they are worn out.)
26. Select a gear ratio that is appropriate to your engine, transmission, and driving conditions. If you travel on the highway often and do not carry heavy loads, try a numerically lower final drive ratio (known as a "higher" gear.) Careful not to go too "high" with the ratio, this can cause smaller engines to work too hard to keep up, damaging the engine. Some manufacturers offer optional gearing.
27. On fuel-injected cars, make sure the oxygen sensors, engine emissions system, and evaporative emissions control systems are in good shape. Often the "check engine light" coming on is an indication that there is a problem with one of these components. A damaged oxygen sensor may cause your car to have too rich of a fuel mixture, decreasing your fuel mileage by 20% or more.
28. Join a good car efficiency forum such as ecomodder forums which also have a wiki with a more comprehensive tested and quantified modification list Wiki

Tips

• If you own an SUV, keep it in 2-wheel drive mode for normal driving as it uses less fuel than 4-wheel drive mode. Be sure to unlock 4-wheel drive hubs to reduce drag. More moving parts in the drivetrain means more friction, more wear and tear, and less efficiency.
• Your fuel mileage depends mostly on your driving habits. Drive conservatively and you'll notice a difference.
• When looking for a new car, always check the fuel consumption rating.
• Manual transmissions tend to get better gas mileage, usually accounting for 15% power loss through the drive train while automatic transmissions suck up about 20% in parasitic loss.
• You can reduce the load on your engine at a red light by putting it on neutral as you're waiting. However, too many shifts between "N" and "D" can cause your transmission to wear out, so avoid using "N" for shorter wait times.
• Some cars that have a crooked shift pattern for their floor shift automatic transmission, have '4' and 'D' on the same row. Many people shift the car past 'D' and into '4' because it 'feels right', then drive down the freeway complaining about bad gas mileage.
• When waiting in line at drive through windows or in gas lines, don't idle the engine. Kill the engine and restart it when it is time to move up in the line.
• For the best fuel mileage in city driving conditions, consider getting a hybrid vehicle.
• 'Regen' recovers far less energy than acceleration requires. To 'coast' further without regenerative braking excessively slowing your automatic transmission equipped hybrid, putting just the right pressure on the accelerator can prevent the 'regen' drag without adding engine power.
• Be cautious of fuel injector cleaners available in parts stores as a fuel additive which, anecdotally, may damage injectors on older vehicles.
• Try to schedule your trips and errands when traffic is light. Doing this will also help your mental health as it will decrease the amount of stress that you will have while driving.
• If you are always stuck in rush hour traffic after work anyway, try to find something to do near your work until the traffic dies down, rather than try to fight through it.
• Try to park 'in the middle' of errands and walk between them. Saves at least a park and pull-out in a parking lot, the slow-motion trip between, and maybe even get you some exercise.
• Vehicle ground effects, aerodynamics kits, and air foils, such as deck-lid spoilers, increase the car's drag, thus lowering fuel economy. Often times such parts serve only an aesthetic value and offer no real handling enhancements. Also, place signs or cargo on the roof so that the smaller face of the piece faces forward. This will lower the frontal area and, thus, lower drag.
• If your car has a roof rack, remove it if possible while not in use. If the entire unit can't be removed, take the cross bars off to reduce frontal area and drag.
• Keep carbon deposits from building in your engine by revving the engine to high engine RPM's about once a week. Interstate on-ramps and overtaking vehicles are good times to do this.
• Avoid drive thrus. You waste gas idling. Turn off the car and go inside.
• Some weight in the trunk, such as a bag or two of rocks, can be good in the winter to improve traction in a rear-wheel-drive vehicle. If the traction is needed the added safety to people and property is more important than the slight fuel expense. Just take out the weight when it is no longer needed.

Warnings

• Driving slowly on the highway may be dangerous. It is usually illegal to drive more than 15 mph below the posted speed limit without having the emergency flashers activated.
• Be careful when using oil additives, some can void a warranty. Read the back of the packaging before use...or consult your vehicles' manufacturer.
• Beware of 'chipping' and other seemingly minor, yet significant vehicle modifications. These will certainly void the warranty, and the wrong one can save fuel and damage expensive engine components for your trouble.
• Beware of quack remedies and testimonials about amazing savings. Every magnet and wonder widget that was debunked in the 70's is back again to tempt a new generation.
• Driving close to another car is *always* unsafe; "drafting", moreso. Driving close to another car also has legal ramifications. Other dangers include the car in front: suddenly hit the brakes or stop, swerve to avoid something in the road, pass over something in the road that your car does not have enough ground clearance to go over, kick up road debris, have an accident. Always remain at a safe distance from traffic.
• Usually a 3 second following distance is most effective for maintaining a safe following distance and to avoid road hazards even if they are hidden by the vehicle in front of you.

Related wikiHows

• How to Predict Traffic Signals
• How to Save Money on Gas
• How to Save Gas when Driving a Car With a Manual Transmission
• How to Reduce Your Greenhouse Gas Emissions
• How to Build a Gas Scooter

Sources and Citations

• Seven Ways to Increase Fuel Economy
• TrackYourGasMileage.com - Keep a track of your vehicle's gas mileage.
• A comprehensive list of quantified car modifications

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How to Increase the Fuel Mileage on a Tractor Trailer Truck

Achieving optimum fuel efficiency is a major concern for drivers of tractor trailers. Extra costs associated with poor fuel mileage have a direct and negative effect on the owners and operators of big rigs. Expenses associated with diesel prices and low miles per gallon are also passed along to the average citizen, who must purchase and consume the variety of goods shipped all over the country in tractor trailers. Thus, it is important to everyone that big rigs get the best fuel mileage possible. Operators have a number of ways to accomplish this.

Instructions

Travel at a speed of approximately 60 mph on the highway. Speeding is one of the major contributors to poor fuel mileage. For every mph over 50, you will decrease your mileage by approximately 0.1 mile per gallon..

Avoid the upper end of the power scale (1,500 to 1,800/2,100 rpm) when starting out from a dead stop. Instead, try to short-shift in the low-range gears between 1,100 and 1,200 rpm. When you shift into high range, use 1,500 rpm as the maximum shift point. Also watch your boost gauge and keep it steady and consistent as you accelerate.

Avoid excessive idling. Generally, no more than five minutes is required to warm up the truck's engine. Idling for a cool-down period is not necessary, as the engine cools while you are parking your rig.

Install a fuel economy gauge if your tractor trailer is not equipped with one. This will allow you to monitor changes in fuel usage and make immediate changes to ensure better mileage.

Repair any damage done to the body of the truck, as this will negatively affect its aerodynamics and decrease fuel efficiency. If possible, also upgrade your truck's airshield and side mirrors (if driving an older truck) to newer, more aerodynamic styles.

Perform routine maintenance on your tractor trailer. This includes regularly replacing fuel and air filters and keeping the tires inflated to the proper pressure. Under-inflated tires ruin fuel economy. When you change the engine, transmission and axle oil, consider replacing them with a quality synthetic.

Use a GPS navigation system to find the best routes to your destination. This will help you to avoid getting lost and burning extra fuel.

Read the owner's manual for your tractor-trailer truck, and study how to achieve the best performance from your truck's engine.