Codes P0181 (Fuel Temperature Sensor Circuit Range/Performance) and P0171 (System Too Lean Bank 1) together suggest a problem related to fuel delivery and/or the fuel system's ability to accurately measure fuel temperature. While the EFT sensor is part of this, the problem might stem from other components within the fuel system:
* Faulty Fuel Pressure Regulator: This is the most likely culprit given the integrated EFT sensor. A failing regulator can lead to inaccurate fuel pressure and temperature readings, triggering both codes.
* Wiring Issues: Check the wiring harness connected to the fuel pressure regulator for any damage, corrosion, or loose connections.
* Fuel Pump: A weak or failing fuel pump can affect fuel pressure and temperature, indirectly impacting the sensor readings.
* Fuel Filter: A clogged fuel filter can restrict fuel flow and affect pressure/temperature readings.
Troubleshooting Steps:
1. Check Fuel Pressure: Have a mechanic or use a fuel pressure gauge to check fuel pressure. This is crucial to determine if the issue is related to the fuel pump or regulator.
2. Inspect Fuel Filter: Replace the fuel filter if it's old or dirty.
3. Visual Inspection of Fuel Pressure Regulator: Carefully inspect the fuel pressure regulator for any visible damage. However, replacing it is often the best course of action since the EFT sensor is integrated.
4. Professional Diagnosis: The best approach is to take your Windstar to a qualified mechanic for a proper diagnosis. They have the tools and expertise to accurately pinpoint the cause of the problem, beyond just replacing parts based on codes.
Simply replacing parts without a proper diagnosis can be expensive and may not solve the underlying issue. The combined codes strongly suggest a fuel delivery problem, and focusing on fuel pressure is the most effective way to address it.
