Want this question answered?
p0171 andpo174 mean that you're car is running lean
P0171-system too lean bank 1 and P0174-system too lean bank 2
It means your vehicle is running lean you will need to replace the intake manifold gasket, as it is plastic and the seal wears out.
Trouble code P0171 means: Fuel Trim System Lean (Bank 1) Trouble code P0174 means: Fuel Trim System Lean (Bank 2)
Trouble code P0171 means: Fuel Trim System Lean (Bank 1) Trouble code P0174 means: Fuel Trim System Lean (Bank 2)
Trouble code P0171 means: Fuel System Too Lean (Cylinder Bank 1) Trouble code P0174 means: Fuel System Too Lean (Cylinder Bank 2)
Trouble code P0171 means: Fuel System Too Lean (Cylinder Bank 1) Trouble code P0174 means: Fuel System Too Lean (Cylinder Bank 2) These 2 codes are common indicators of a well-known failure on the 1999-2003 Windstars. Be sure to review the additional information in the "Related Questions" below...
Read through the "Related Question" that discusses a common problem with the Windstars and rough idle - check engine codes P0171 & P0174. That might be part of your problem too...
P0171 - system too lean ( Bank 1 ) - passenger side of engine P0174 - system too lean ( Bank 2 ) - drivers side of engine
P0171, system too lean (bank 1). P0174, system too lean (bank 2). Start with checking for a vacuum leak.
Lean condition detected on banks 1 & 2 (left and right sides). Most commonly a dirty mass air flow sensor, or possible vacuum leak.
Bank 1 and bank 2 is running lean. I would suspect a vacuum leak. Check for cracked, disconnected or broken vacuum line(s). The fuel filter could also be plugged and restricting the flow of fuel.