P0171 Ford - Where is the best place to begin in order to clear this issue?

Question

I have a 2006 Ford Freestar and have gotten only code P0171, vehicle will start then dies after 2-3 seconds. Where is the O2 sensor on this engine and is this actually the best place to start in order to clear this code?

Answer 1

P0171 Fuel trim lean

The 02 sensor is not going to be the cause of this code , What you have is a condition if the vehicle will start and dies in 2 to 3 seconds. Vacuum leaks can cause this code condition and so can low fuel pressure. In order to look for the cvacuum leak the engine has to start and least be at idle. for now look for any vacuum lines that may have got disconnected or even ruptured at the PCV valve area.