I have a completely stock 2012 2.5L MTX Outback with about 200k miles. I have had a P0171 code that shows up when idling for longer periods (more than 3 mins). I did recently replace the MAF, Front O2 sensor, and PCV since I am around 100k since last replaced and it was the first suggestions when referencing this code. I borrowed a buddy's scanner to look at A/F values but I do not know how to evaluate what is going on and how to deduct what to look at next. Can anyone walk me through what values I need to look at and what to do next with the vehicle?