fuel econemy on 2005 Hyundai Santa Fe

my 05 santa fe gets bad gas mileage in town. i just did the 30.000 mile service [not with the dealer] the owners man. says to replace the intank fuel filter and the inline gas tank air filter? i called the dealer and they said that they didnt even replace the fuel filter.what about the inline air filter? and where would i find it?

Asked by for the 2005 Hyundai Santa Fe