Going back to the original post, here are the big items to look at.
- Spark plugs – if you are running on the stock plugs (and you probably are) it is time to change them. IMHO the best plug for you is the NGK OE laser iridium or the NGK iridium IX, the best part is once you change them you should never have to bother with them again.
- Front oxygen sensor-if your car has over 120k replace it. This is the most important fuel related sensor in your car. A slow/old O2 sensor can destroy your fuel economy.
- Don’t idle your car if at all possible. "Warming" your car up, drive-thrus, any idling eats up gas unnecessary. Just remember idling = zero mpg
- Proper tire pressure = the very minimum pressure you should ever run is 30psi, and even then only for track day. IMHO the best pressure to run for improved handling and mpg is ~33-35psi.
- Dead weight-get rid of anything in your car you don’t expect to use that day. And if you feel lucky that could mean your spare tire.
- Drive smooth and roughly the speed limit, use cruise when ever practicable, use the A/C when you need to otherwise crack a window.