This is a good list - jeffreykime.

Let's rank them starting with those that hurt your fuel economy the worst:

The two most important

• 5 - Jack Rabbit starts (Stop-and-Go) If you look at the instant mpg bar (those of you that have one), fuel economy plunges. If you intend to get a lot of miles on a tank, you will accelerate gently. Two things that hurt your trip mpg quickly is the catalytic converter warming up (can't do a lot about that) and moderating accelerations. This is true of my 2000 Insight and 1974 Opel Manta, so it may be a good generalism for most vehicles: Your fuel economy doing Fast and Furious type of stop-and-go driving at 40mph will be as bad as a steady cruise at 80 mph on the freeway. Conservating momentum is the most important thing to improving your fuel economy
• 10 -Wind Resistance (Speed) If you read the little message on the Shell Gas pump, you may have noticed "highway speeding can reduce your fuel economy by as much as 33%". Ballpark this would be the difference between doing 80 and doing 55 or 60. Wind resistance goes up geometrically and become a bigger factor than weight.

Also Important

• 4 - Hills - It simply takes more energy to go both forward and up. One way of cutting your losses is gradually increase your speed as you approach the hill. Depending on how big the hill is, try not to give it a lot of gas and allow your speed to drop some.
• 8 - Weather (temp and rain) If it's severe, this hurts maybe more than anything else. A severely iced road makes driving over 20mph dangerous. High wind and rains also make a severe impact.
• 1 - Air Conditioner on. Even with afternoon highs near 100F, it's possible to use the A/C very lightly if you are not dressed in a shirt-and-tie. Use a shelter (garage or tree) whenever you can. Toggle the A/C on when braking, coasting, stoping - fan only otherwise
  
  

Generally not that Critical

• 2 - Cruise control use. Actually I'm not that sure, but my cruise control experience is not positive. It works better on large and performance vehicles and not so well on subcompacts. Fuel economy will be hurt is there are a lot of hills.
• 3 - Full tank vs. half tank of gas
• 6 - Low Tire pressure. Might be significant if pressure is really low.
• 9 - Weight in trunk At most this is a couple of hundred of pounds. Wind reistance is much more significant.

61.5mpg lifetime - 82mpg in recent months

Best Run >
www.cleanmpg.com

"fanatic" is what the lazy call the dedicated