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International Automotive Technicians Network
Re: 2004 F150 5.4 '5' Lean codes P0171 and P0174
Posted to Technical Discussion Forum on 2/24/2009

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General concensus here was non-laminar, or incorrect airflow across MAF due to aftermarket cold air intake pipe. Customer elected not to fix it. My next step was to obtain a factory air inlet before ... Login to read more.