Question

I have a 2003 Ford F150 4.5L and I'm getting p0171 and p0174 codes. changing MAF did not fix the problem.

Answer 1

Hi there,

If replacing the maf didn't resolve the issue then the next step would be to check the fuel pressure. If it's low it will affect both banks on the engine and store these codes.

Answer 2

P0171 FORD - Fuel Injection System Too Lean Bank 1
Read more: https://www.autocodes.com/p0171_ford.html

P0174 FORD - Fuel Injection System Too Lean Bank 2
Read more: https://www.autocodes.com/p0174_ford.html