the fuel supply will be set by the o2 sensor being out of the the factory range .250mv to .850mv if the o2 sensor spends more of the time out of range then it will throw this code. first off did you do something fuel related to the car? if not check for a clogged cat clogged a dirty fuel filter or o2 sensor. if you have a o2 sensor lying around and you dident do anything fuel related i would try that first