Can not get rid of PO171, PO174

[Corinthians]

I have a 2003 Sporttrac with 115000 mls no matter what I do the codes come back. Any suggestion please.

 

[swshawaii]

PCV elbow is the most common cause for p0171 and 174 lean codes. Very important to inspect the bottom side.

P0171 & P0174 4.0L SOHC's Sport/Sport Trac

 

[Corinthians]

I'v done that and they come back. I'll give you a list of what I have done.
Replace intake
Check mass sensor
Replace air and fuel filter
Replace injectors
Replace PCV valve and hose
New spark plug and wire
Reset com
These are the codes from hell.

 

[swshawaii]

Lean condition procedure