PCV elbow location?

[DoctorRoboto]

All,

I just got a '98 Ranger 4.0L, which came complete with a set of P0171 and P0174 error codes. The PO has previously swapped 2 O2 sensors, I was thinking about trying to find which ones and swap the other 2. Before I did, I wanted to check on some of the cheaper and more likely culprits - the PCV components. From reading online, it looks like the PCV elbow cracks and gets a true vacuum leak, instead of a faulty sensor and no actual vacuum leak. I can't find the PCV valve or the elbow, though, and was hoping for some help on my specific engine.

Attached are two photos of my engine compartment. Where am I looking for this elbow?

 

[RonD]

Looks like a clean truck

Not sure why people replace O2 sensors with Lean codes on both banks, P0171 and P0174.

It would be same odds as winning the lottery to have TWO O2 sensors fail at the same time.

But if upstream O2s are over 125k miles then new ones will get your MPG back up a bit.

First step is to test for a vacuum leak which is very easy
Warm up the engine, normal operating temp
Auto trans should idle at about 750
Manual trans 650
With engine idling, unplug the two wire connector on the IAC(idle air control valve) Valve

RPMs should drop to 500, or engine may even stall, either is good, it means no vacuum leaks
If idle stays at or above 700 then you have a leak
Leave IAC Valve unplugged with engine idling and pull off 1 vacuum hose at a time from the upper intake and plug the port with your finger, if idle drops you found the hose/system with the leak.
Start with PCV hose and Brake booster hose.

FYI, the PCV Elbow issue was on the 2001 and up 4.0l SOHC engines, you have the 4.0l OHV, it could still have a cracked or broken PCV hose just not a common issue with 2000 and earlier 4.0l OHV engines

If idle drops to 500 or engine stalls then you do not have a vacuum leak.
Could be dirty MAF sensor, clean it
Could be an air leak in the Air Tube from MAF sensor to upper intake, check it
Could be dirty fuel injectors, Seafoam in the gas tank will clean them up
Could be low fuel pressure, test it, 1998 should be 60-70psi
1997 and earlier Rangers were 30-40psi

Because BOTH banks of the engine are effected it will have to be upper intake issue, MAF sensor or fuel flow/pressure, because both banks use/share these, lower intake or O2 sensor would only effect 1 bank