I have a 97 F150 4WD, 5.4L 117,000 miles. Check engine light recently came on and truck started idling poorly(severe miss), and stalling when stopped. Idle problems only seem to happen when engine is warm, runs fine cold. Pulled codes and got P0171 and P0174. Lean mixture in both banks. My research indicates that the most likely cause is a bad MAF or EGR. Is there any way to narrow down the cause instead of just throwing parts at it. The problem came on suddenly, not gradually. Plugs, fuel filter and other maintenance items were replaced less than 20,000 miles ago, and O2 sensors replaced about 5,000 miles ago.

 

Please disregard this post. I didn't see my original "MAF or EGR" and thought I had deleted it accidently