Codes p0171, p0174

[kimcrwbr1]

just hook everything up according to the vacuum diagram under the hood if not I think the tech library has a diagram or someone here can get you one. plug everything not being used check all wires grounds and connectors make sure everything looks good get it running and run codes. running at it blind dont work too well fix the obvious first plugs wires filters oil change get the preventative maintenance up to date then continue to troubleshoot

 

[redstangs9308gt]

If any yall friends have a 2000 4.0ohv I would really apreicate it if you could find out where that small vaccum line is going off of the PCV valve. I looked at the diagram but it isn't clear where its meant to hook up at. I made a diagram of what I need on Paint but I can't figure out how to post it on here. Shew dang problems

 

[kimcrwbr1]

If you cant find somewhere to connect and all your emissions is hooked up dont worry about it buy a little rubber cap and be done with it mine comes with that type of pcv they give you a plug with the new one

 

[kimcrwbr1]

I checked in the tech library under vacuum diagrams It just needs to be plugged on a 1999 4.0

 

[redstangs9308gt]

Update, I have drove and completed a bunch of duty cycles to see if the computer was going to throw another check engine light and guess what NO CHECK ENGINE LIGHT weeee haaaa.
To anyone with these codes this is what I done and what order before I got rid of my lean codes.
1. Cleaned mass air flow
2. Changed fuel filter
3. New o2 sensors
4. New mass air flow
5. New air temp sensor
6. New upper plenium gaskets
7. New upper intake gasket
8. New lower intake gasket
9. New bottom intake gasket
10. Cleaned injectors with either
11. New egr
12. New pcv valve
13 New idle air control motor
14. New throttle body gasket.
After I started tearing deeper into the motor I started seeing a common issue all gaskets from the throttle body gasket to the valve gaskets was leaking and or cracked or shrunk or hardened. So I replaced every gasket I could and sensors. I even changed my valve cover gaskets. I am at 137k so to anyone having these problems this is a good place to start after exhausting the cheaper and easier methods....PS all the hardwork and money was worth it. Truck is running GREAT.