Possible issues associated with p0171 code on 2007 ford focus ses.

Question

I have replaced all three oxygen sensors. Engine light comes on. Replaced fuel pump and filter based on a diagnotice test performed at Ford dealership. Fords code reader came up as code p0191. Attached fuel pressure gauge and showed up as 21 psi when it should be 39 psi. Hence the changing of the fuel pump & filter. Engine light comes on. What is the next most probable issue associated with this code?

Answer 1

P0171 Fuel trim lean Bank 1

There is only one place that will cause a P0171 and that is the PCV hose, just a small hole in the PCV hose will set a P0171.

 The PCV and it the PCV hose is located behind the intake manifold, Replace the PCV hose and P0171 will be resolved, and make this a hobby in replacing

Comments

Not true. I replaced my pvc valve and hose and still keep getting a p0171 code after resetting.

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Try a MAF sensor cleaning, Since the fuel filter and pump was replaced your going to have to get a fuel pressure / volume tested.