A lean condition can be caused by several things:
* Faulty oxygen sensor(s): The oxygen sensor(s) tell the computer how much oxygen is in the exhaust, allowing it to adjust the fuel mixture. A bad sensor can provide inaccurate data, leading to a lean condition.
* Mass airflow sensor (MAF) problems: The MAF sensor measures the amount of air entering the engine. A malfunctioning MAF sensor can cause the computer to inject too little fuel.
* Vacuum leaks: Leaks in the intake system allow unmetered air to enter the engine, upsetting the air/fuel ratio.
* Fuel injector problems: Clogged or malfunctioning fuel injectors may not deliver enough fuel.
* Fuel pump issues: A weak fuel pump might not provide sufficient fuel pressure.
* Improperly adjusted fuel pressure regulator: This regulator controls fuel pressure; if it's malfunctioning, the fuel pressure could be too low.
Consequences of a lean condition:
A lean running engine can cause several problems, including:
* Reduced power: The engine won't run as efficiently and will feel less powerful.
* Overheating: Lean mixtures burn hotter, increasing the risk of engine damage.
* Misfires: The engine may misfire because the fuel/air mixture isn't igniting properly. This can lead to damage to the catalytic converter.
* Check engine light: The check engine light will likely illuminate, and a diagnostic trouble code (DTC) will be stored in the car's computer.
What to do:
You need to get your Ford Windstar diagnosed by a mechanic. They'll use a scan tool to read the diagnostic trouble codes and check the various components mentioned above to identify the root cause of the lean condition. Ignoring the problem can lead to significant engine damage.
