With gas prices soaring all over the US, this topic becomes hot in America, too. Finally Americans joined the rest of the world in a desire to save some gas. Here are some tips from former engine designer that will help you to protect your wallet a bit.
1. Try to keep things in perspective. Remember, that your goal is to spend less money overall. Spending $1500 on a tune-up with expected savings of $1 per tank fill is not going to cut it. This is not to say you shouldn't do a tune-up at all. If time for it comes, by all means go ahead and do it, regular tune-ups are important to your car well being. However, from gas saving perspective you want to implement the least expensive (zero cost ideally) measures that give you the best savings.
2. Keep your tires properly inflated. Check the pressure at least every time you fill your tank. Most modern cars have a label that lists proper tire pressure, your owner's manual has this info, too. Some people suggest inflating tires up to the maximum pressure shown on the tire wall. If you do this, you will get higher thread wear in the middle of a tire on most cars, and you'll have to replace tires early. I don't think the marginal gas mileage improvement because of higher tire pressure is enough to offset extra costs of early tires replacement.
3. Don't haul anything you don't absolutely need. Check your trunk, glove box and cabin for belongings that do not have any business being in the car on a permanent basis. This does not save you much (unless you have a habit of driving with the full trunk all the time) - but it does save a bit, and it does not cost a dime to implement.
4. Don't stomp on gas. Acceleration takes a lot of gas. The slower you accelerate, the better your gas mileage is. On the other hand, if you accelerate too slowly, drivers behind you will get mad at you. Everybody strikes his own balance on this.
5. Don't slam on brakes. The more you brake, the more you have to accelerate afterwards, and this costs you more in the end. Ideally you want to accelerate once, and then drive at the constant speed. Of course ideal is not achievable, but the closer you get, the more gas you save.
6. Avoid excessive idling. This does not mean to turn off your car at the red light or when coasting in neutral. Such things are unsafe, and you'll consume more gas when you start your engine back. But try to avoid parking or standing for any prolonged period with your engine on. Remember that your engine gives you 0 MPG when idling.
7. In a hot weather, turn off A/C and open windows while driving in the city if possible, and close windows and turn on A/C on highways. At higher speeds (around 50 MPH and up) aerodynamic drag becomes a major gas eater, at lower speeds A/C consumes more.
8. Optimize your route. The less distance you drive, the less gas you use. If you have to visit several places, see how you can route your trip to have the minimum number of miles driven.
9. Plan your route to avoid traffic jams. You can't avoid excessive idling, braking and acceleration while in a traffic jam, so jams are responsible for a big chunk of gas consumed. You can avoid jams sometimes however if you learn traffic patterns in your area and use them to your advantage.
10. Consider walking or using a bicycle for short distance trips, or using public transportation if convenient and cost effective. Yes, you save gas (and money) when you are not using your car.
All those tips will not turn your 15 MPG truck into 40 MPG compact, but they definitely give you a noticeable improvement, if you follow them.