Well yours is an 02...how many miles? A couple small mods i've done that arent too much of a price gouge.
Changed my oil to Royal Purple. I got about an added 2.5 mpg to my car once I started using that. It polishes the bearings and such reducing friction, adding a couple hp, and it says change every 12k miles. (i will change it at 10, filter at 5).
Sea foam - If you have about 25,000+ miles on your car dump a can of that in your gas tank. $5 from autozone and works wonders. I got another mpg to that.
Shift around or under 2,000 rpms
stay under 68 mph. 68 is where your car goes at the highest mpg. (freeway speed of course...or backroad...)
under drive pulley - it's my next mod.
dual exhaust - gives about 2 mpg
intake - gives about 1 mpg
If the previous owner put a pref. chip in it, then it would require premium gas. so if you're not using 93 octane it probably doesnt have one.
I'm geting about 28 mpg top up highway driving no a/c.
City i avg about 24. I also have a 300 watt amp so that takes away a little.