The P0171 code for Toyota indicates a lean air-fuel mixture in the engine. To fix this issue, you should inspect and potentially replace the mass air flow (MAF) sensor, check for vacuum leaks in hoses and intake manifold, and examine the fuel system, including the fuel filter and fuel pump for proper operation. Additionally, ensure that the engine is not experiencing any other issues such as spark plug or ignition coil problems that could contribute to the lean condition. After addressing these components, clear the code and perform a test drive to see if it returns.
Trouble code P0171 means:System too lean (Bank 1)
Trouble code P0171 means:System too lean (Bank 1)
Trouble code P0171 means: System Too Lean (Bank 1)
Trouble code P0171 means: Fuel System Too Lean - Bank 1
Trouble code P0171 means: Fuel System Too Lean - Bank 1
Trouble code P0171 means: Fuel System Too Lean - Bank 1
Trouble code P0171 means: Fuel System Too Lean (Cylinder Bank 1)
Fuel trim rich.
http://www.aa1car.com/library/ford_lean_codes.htm
Start with looking for a vacuum leak.
Trouble code P0171 means: Fuel System Too Lean (Cylinder Bank 1)
P0171 = System too Lean (Bank 1). I would start by looking for a vacuum leak under the hood.