If you really want to reduce your fuel costs then don’t drive. Simple, but true, try walking, biking or talking someone else into using their gas.
If you are going to drive your own car and use your own fuel then the most effective thing will be to reduce weight. Go through your vehicle and see what you can take out. Weight is the biggest contributing factor to gas mileage. Guess why Hummers get such crappy mileage? Get a car that doesn’t weigh much or reduce the weight of what you have. So clean your car inside and out as well as rinsing dirt off the underside and wheel wells. If you want to clean the engine compartment wait until it is cool and spray it down with Simple Green and rinse. Do that a couple of times and you will have a sparkling engine compartment. You will have gotten rid of dirt and its weight, and you will now be able to notice any leaks or problems much quicker.
Keep your tire pressures where they should be. Take the factory recommended pressures (usually on a sticker in the door jamb) and boost them up by two or three pounds. You might end up wearing the middle of the tire’s tread, but you can often cut the rolling resistance down. Just be aware that it will mean a harsher ride and you need to be cautious about wear and handling changes.
Use nitrogen in your tires. Your tire pressures will be much more stable and it will show up in better gas mileage and longer tire wear. Normal compressed air contains a lot of nitrogen, but it also contains oxygen and water vapor, among other things. Its not snake oil – nitrogen works.
Get a tune up. Forget buying miracle magnets or turbo intake twirlers that claim to increase mileage by at least 10%. Perform the maintenance that should be done like changing spark plugs, wires, coil packs, air filter, gas filter, etc. Change your oil and rotate your tires (if possible) on a regular basis.
Make sure your car is aligned. While getting it aligned the technician will be able to tell you if you have ball joints or tie rod ends that are worn or damaged. Replace them, if necessary. Those worn items will cost you in fuel and affect the safety of your vehicle.
Drive like fuel costs $20 a gallon. Pretend you have a raw egg under your foot. You will piss off the drivers around you, but you will save fuel if you ease on the gas ever so gently and minimize your use of the brake (be safe – use your brakes to keep out of trouble). Adopt as smooth a driving style as possible. Sitting at stop lights you are getting zero miles per gallon. You might want to shut off the car if you know you will be stopped for a while, like at a railroad crossing or waiting in line to fill up.
It costs money to drive a complex vehicle like we have today. Don’t take it for granted. Keep it maintained and clean. Don’t haul around unnecessary weight. Drive smoothly and carefully. Don’t drive if you can avoid it and plan your routes ahead of time.
Gas will not get any cheaper and someday it will essentially be gone. Try the above and save your money for an electric car.