What are the possible causes of the code?
Engine Code: P0171 on 1999 Ford Contour
The OBD II P0171 means the Fuel System is too Lean (Bank 1). Your vehicle's computer registered a fault in the emission system. It detected abnormal levels of oxygen in the exhaust. For much more information please refer to this very interesting article in the Encyclopedia; http://repairpal.com/OBD-II-Code-P0171-and-P0174