I pulled codes from my ecu today. I got only a code 55, Normal engine management system operation is indicated. Car seems to be running pretty good. I have been trying to drive like a granny and my gas mileage still is not as good as it should be...I did 100miles freeway driving and the rest city...I got maybe 16-17mpg with 100miles highway, 60+...I have wsp 2 1/2" exhaust y-pipe all the way back, cold air intake, asp pulley. I should be getting better gas mileage with those add ons shouldn't i?