1. First of all, remove the aggressive tendency from your driving habits. I admit I myself like to be aggressive sometimes, it gives me chills, diesel cars have a lot of torque at low rpm, but from what I experienced that go fast-full stop-go-fast attitude costs me about 2 liters more per hundred kilometers. Sometimes it’s worth it, but there are few situations to sustain that.
2. As with gasoline engines, idling gets you 0 MPG, because you are going nowhere, and suddenly all the money you spent on fuel to move you go into the air for nothing. They even pollute the atmosphere… yes, the money you worked for.
3. Keep right on highways so other fuel-wasting drivers can pass, and mentally/emotionally detach yourself from the stigma of being a “slow” driver. The only competition you can truly win is at the fuel pump.
4. Try to drive on the most uninterrupted routes, on those with the fewest stop lights, and less crowded. Not always the shortest route is the fastest one, choose your own by experience and by adaptation to the traffic conditions. That’s a no brainer choice.
5. Each engine has a point where it operates most efficiently. These are normally “highway speeds” somewhere around 60 mph (100 kph) in 5th gear but it will vary from car to car. Accelerating to that habitual “20% over the speed limit” will negatively impact your fuel consumption considerably.
6. If you have cruise control in your vehicle, use it on a regular basis so that you don’t tend to accelerate too much. Your onboard computer is better at efficiently maintaining your cruising speed than you are. Humans tend to “over correct” by accelerating a little too much, braking or decelerating, applying the gas pedal again, etc. This wastes fuel, a little at a time. And it’s even more relaxing not standing with your foot on anything, and admiring the landscape. Not too much, of course, you still have to pay attention to the traffic :).
7. Use your higher gears as soon as you can. Some say it’s better for the engine to over-rotate it, but that spends more fuel than necessary and decreases the engine’s life. It’s a universal law: use it gently, it will last longer. Also, don’t exaggerate with this habit. When you see your engine beginning to stall, shift to a lower gear. Normally, if you are in a higher gear and the engine doesn’t “pull” anymore you are tempted to push the acceleration stronger, and that tells the computer to squirt more fuel. Taking your drive to a lower gear indeed, gets you higher with a couple hundreds of rpm but it also gets you faster up the hill with less fuel.
8. Some dealers offer tune-ups for your onboard computer that upgrade your vehicles fuel economy. Many people purchase these expensive chips without considering their cost. These chips should be viewed as an investment. Armed with numbers of your regular fuel consumption, average speeds, etc, you should calculate how long it will take the chip to pay for itself. Some discover that it is longer than they plan to own the vehicle, making the purchase unworthy. On the other hand, in the environmental point of view, not considering the money spent on that upgrade, less fuel used means less pollution, so you must think of that, too.
9. Do not use your engine brake to stop. Coast to a stop either in neutral or by holding the clutch down. Using engine brake (gearing down) wastes a lot of fuel. It’s true that this is a harder job for your brake pads, the difference is insignificant, and your clutch will not wear out as quickly. Brakes cost less than clutches do, and when combined with the gas you are saving, it’s a far better choice.
10. Many drivers forget that every electrical convenience being operated consumes fuel. Try to keep high consumers like defrost, seat warmers, fans, etc at a minimum. Turn off your full lights during the day and let your day running lights do the rest. Also, many defrost options will not turn off automatically, so monitor them with care. Air conditioning is the worst fuel-consumer. Use it only as necessary if you wish to conserve your fuel. Turning the windows down also wastes fuel, although some people argue whether or not it wastes more or less than air conditioning, and this fact varies at different speeds. The fact is, any time air is being removed from the passenger cabin through an opening, it is creating some degree of drag from an aerodynamic standpoint, however small. Simply be aware of it.
11. When you finally empty your tank, note your “Trip” odometer reading. This should act as your “score” of how many miles/kilometers you managed to get out of your vehicle on that tank. Also note the amount of fuel you used to fill your tank in gallons. Miles / gallons = MPG. Beating this score becomes the goal by experimenting with different driving patterns, speeds, routes, fuel, additives, etc. Just remember to make small changes, one at a time, or else you will never know what is working for or against you.