*Posted on the Expedition forum as well

Ok, I have searched this for some time but cant really come to a conclusive decision. I throw the p0174 code about once a month. I just figured out today that the O'riley scanner reads FF data as well and this is what it had

Po174
LTFT Bank 1 = 9.3%
STFT Bank 1 = 5.4%
LTFT Bank 2 = 8.5%
STFT Bank 2 = -0.7%
Engine idle was 850 rpm
Temp was 170F
Fule loop was closed
Load was something like 64-68%

What do you guys think it is? I have looked at the PCV tube but it is also covered with insulation so I really can't inspect the whole line. The elbow look ok but is there some what to check it? I heard someone say to spray carb cleaner on it?? With times the way they are, I would rather not just start replacing parts (O2 sensors) to find it if I dont need to. I am kind of crossing my fingers that it is... they are somewhat cheap

BTW, 2001 expedition 5.4. Seems to run fine when I am in it. Its the wifes ride. No hesitation or stuttering on idle. Seems to run smooth...

Thanks for any help

 

To help you see the relationships, the code 174 is for bank 2.
Look at your fuel trims for bank 2 as compaired to bank 1.
The bank 2 long and short fuel trims shows an issue that is marginal so may set a CEL at times then go away.
This is why you feel no drivability issue but the computer detects the issue long before it becomes a drivability issue.
The trick is knowing what the 174 code is telling you.
It says the #2 fuel table is shifted to far to the rich side trying to account for to much air.
But other causes will shift it as well.
Being it's only one bank, look at the possibility of an intake gasket air leak on that bank, exhaust pipe crack etc.
Otherwise anything common to both banks would set code for both.
Do not change the OX sensor because it is only the way the system has of detecting there is an issue up stream so is only reporting the trouble.
Good luck.

 

Please do NOT cross-post the same thing in multiple forums.