96' Taurus LX problem

96' ford TaurusLX 75'000 miles 17-21mpg
Starting the car it starts rough
idles rough
and if the ac/vent was running on the car I could smell gas fumes
the car idles around 500-700rmp which I know for this model car is very uncommon unless there is a problem
the check engine light isnt on though was on for about 10min about a week ago, turned car off and on and light vanished

my theory (im not in anyway a mechanic) from what ive read and heard from rumors is the car is starving for Oxygen considering im getting the smell of gasoline in the cab

oh also once I get moving there arent any problems when driving except once I hit the gas pedal the car shoots forward and jumps to the proper RPM when accellerating

any ideas? I need to get this solved quickly beccause I have some serious driving I need to be doing this weekend = /