Came across this , might help .
Gen 4 24V Simultaneous Codes P0171 and P0174 Solution
My car is a 2000 Duratec Vin codes "S".
Another Taurus forum I frequent has been having a lot of these codes lately on 2000 and newer models. A couple of weeks ago I threw the P0171 lean code. I cleared it and ran 5 or 600 miles and then threw P0171 and P0174. This means that both banks are showing lean. Later on, my car started running rough when I started it in the cool morning and it did it every morning thereafter. After doing some research and then acquiring the parts to fix this, it has pretty much been agreed to by other people that have had the same problem.
The problem: The rubber tube that connects from the upper intake manifold and goes down into the PCV valve deteriorates ,gets a hole in it and collapses. This causes a vacuum leak which triggers the lean codes. These are the parts needed to fix the car:
--YF1Z-6A664-AB which is a rubber and steel hose assy available only from Ford. It is about 23 dollars at the dealer and 12 dollars at the online ford places.
--You also need the PCV valve which is Motorcraft part number EV-243/YF1Z-6A666-AA. Please be aware many parts stores have this PCV valve listed wrong.
Some people may be able to fix it differently than I did but the following procedure is they only way I could do it and I am a fairly Decent wrench:
--Take the upper intake manifold off and disconnect all hoses , electrical plugs and fittings off.
--Pull the wiring harness up and out of the way.
--Get a pair of 90 degree needle nose pliers to be able go grab the PCV valve and turn it counter clockwise to get it to come out.
--Put the new PCV in .
--Attached the new hose assembly and then put the upper intake on using new gaskets.
This will eliminate the codes and restore a smooth idle and better gas mileage.
The below prices are from January 2010 at Rock Auto.
Intake Manifold Gasket Fel-Pro MS92586 $ 14.00
PCV Motorcraft EV-243/YF1Z-6A666-AA $ 10.41
PCV Hose Motorcraft YF1Z-6A664-AB $ 13.45
This is what I am showing now on my 2000 Sable with the Duratec.
I was at the dealership the other day to get parts for my grill (plastic sucks after 11 years). and decided to get the PCV valve, as I had similar promblems in the past , but mostly high idle (dealer and shops couldn't locate the issues after 100's of dollars. Mechanic friend of mine in the Navy said it was the PCV valve. Bam, sure was. 20 dollar part, 1 lunch for his quote, and ticked at the $$$ spent.
Now, back to curent issue, I am learning with cars, but am having fun after just replacing struts, tie-rods, wheel hub bearings and sway links. (it felt good)... Saved money.
Engine light came on. It was running rough. These codes.
So today, I started to check for vacuum leaks, after watching some You Tube and all, and it was mentioned about the PCV hose.
Sure enough, the elbow part going into the ??? (the other end where the PCV valve) was collapsed and cracked. So, I am hoping that is it.
Wife has the other car, so am stuck.
Question after all my babbling..
Preformed elbows? (reinforced to prevent collapse), do they exist?
I hate to put in just any regular hose and go through this.
I just figured I would replace the PCV valve again anyhow, as it has been 50K miles, and the car has 133K miles on it.
Would this give the same error codes?