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Learn about driving with load, FAS, EOC, codfish.
Recognize that you'll get better mpg at 10-15 mph slower than whatever speed you've prolly been driving even if you change nothing else.
Pump your tires to the max stated on sidewall labeling. Or a few pounds over if you dare. Make sure they're at that pressure when cold in the a.m. before starting up. Usually that means pump them to a few pounds over max sidewall, then check in the a.m. and adjust if needed. Next time you buy tires make sure they're rated at least 44 psi, maybe 50+ if you can.
Put in a clean oem type air filter. Forget K&N. For max FE you're going to be using less fuel-air mixture, not more.
Currently getting +/- 50 mpg in fall weather. EPA is 31/39 so not too shabby. WAI, fuel cutoff switch, full belly pan, smooth wheel covers.