Hello From Orange County NY
 

I presently have a 2000 Mazda 626 LX that I'm looking to make it more fuel efficient. I plan on getting the Scan Gauge E and also plan on doing some other modifications

I haven't read to much about people using Performance chips or Tuner/Programmers is there a reason why?

Welcome,
you are at probably the most informative fuel economy site out there.

......because the are for more hp. Not mpg.
Your better off (bang for the buck)
1. focus on driving effeciently
2. getting a scangauge and keep one of the screens on avg mpg
3. doing some of the mods suggested in the '65' list

Thanks, I always thought the programmers offered settings to save in fuel.

I will take a look at the list thanks!

Welcome to EM! Hondata does offer some fuel saving chip tuning, and the more recent Civic ECUs apparently make it easier... 2005 and forward apparently the Hondas' ECUs practically invite tuning. Hondata does tuning for the 2005-present Civic HX models, IIRC what I saw on their site. You have to mail them the ECU, I think. Don't know if you have a Honda. But it is true that nearly all of Hondata's interest and business appears to be for more HP not more MPG.