HI i have a 2002 galant the 4 cyl, 2.4 L.....It has poor fuel mileage, i have replaced the front 02 sensor, spark plugs, basically i have done a tune up on it and it still burns a lot of gas... i get about 150 miles on a full tank of gas! i waste about 45 dollars a week on gas ........any recomendations? or tips? oh and by the way i used champion spark plugs and i heard that mitsubishi should use ngk spark plugs and that that might help my milieage..