2003 Ford Expedition 4.6 hum/whistle at idle


hey community, as the title suggests my vehicle is having this weird idle hum/whistle that starts after the car reachers operating temperature. It idles somewhat rough at times and almost wants to stall unless I press the accelerator. I also keep getting p0174 (system bank 2 too lean). Anyone have a fix they can suggest? Thanks! 😀