I commute roughly 160 miles a day for my business. The best things I have found maintenance-wise to save gas is: keep your vehicle tuned, replace the air filter as needed (spend a little more on a K&N filter and keep it clean yourself to save even more money), proper tire inflation for the tires mounted on your vehicle- and follow manufacturer spec on tire size and ratings, regular oil changes (don't spend extra $$$ on the synthetics- regular oil works just fine under normal driving conditions).