2000 Windstar 3.8 codes P0171&P0174 (fuel lean)Need help with the latest fix does it still call for upper plenium and valve cover, pcv hose and pressure regulator tube? 02s are switching good ,Any driveability techs please help

 

Is there any driveability problem? If a little under head ecceleration, I'd be looking at a fuel filter. If its been replaced recently, check the fuel pressure. This code could even happen if the O2 sensor was bad but within spec ie. reading lean all the time. But, I suspect the computer would richen it up to much causing black smoke, idling problem or another driveability problem.
Try the fuel filter first.

 

Try replacing the upper intake manifold gaskets. Parts cost around $15.00 from dealership (set of 6 gaskets). Takes about 2 hours to replace. Reset computer by disconnecting the battery for about 20 minutes. Hopfully this solves your problem. It did with my 2002 Windstar with 3.8L V-6 engine and saved me several hundred dollars from the dealership.

 

LOOK AT THIS WEBSITE.... http://leckemby.net/windstar/windstar01.html