you guys are great thanks. I got a 4.6 in my SC think its the same part number?

 

Might be different due to the 5.4L being wider, but it's worth a shot.

 

Had the same problem, except, after replacing the PCV lines the engine warning (lean bank 1) still comes on after about two or three days for no apparent reason whatsoever. Engine runs and performs fine. Does anyone have an idea why the same code keeps coming up after such apparent delays? Sensor maybe?

F150 5.4 litre step side 4x4