Ford F-150 5.4L engine codes PO171-174 with vacuum leak at PCV elbow on Ford F-150

Some Ford F-150 5.4L owners report experiencing issues related to engine codes PO171 and PO174, which indicate a lean fuel mixture on both banks of the engine. A common cause for these codes is a vacuum leak at the PCV elbow, particularly at the connection near the throttle body. Owners are advised to inspect the PCV elbow and all vacuum hoses for signs of leaks, as these are often responsible for triggering the diagnostic trouble codes. Additionally, some owners find that cleaning the Mass Airflow (MAF) sensor can help eliminate issues caused by dirt buildup. It's also noted that the PCV hose may disintegrate at the elbow, leading to further complications. For assistance, AutoZone offers services to check engine codes, and in some cases, disconnecting components like the MAF sensor can help diagnose potential problems, including faulty O2 sensors. Addressing these concerns promptly can help resolve the engine codes effectively.