Well, anyone with bad gas milage, I would suggest running a good fuel system cleaner, maybe even concentrating it some by running it down to half a tank or little more, putting in fuel system cleaner, then splashing maybe a half gallon of gas to mix it up. Other than that, air filter, have O2 sensors checked to make sure that they are working properly (a slightly clogged O2 might not throw a code becuase it might still be in range, just not making correct compensations in A/F ratio). Make sure you don't have clogged cat's, no vacume leaks. Other than that, the more efficient you make your engine to a point, the better gas milage you will get as with performance too... as in freeing up the intake side and exhaust side a little (K&N, Exhaust). But those are my suggestions to you who have bad gas milage.
