Hello everyone. I have a 2006 ford ranger 3.0L that I recently purchased but got kind of screws on. 😡 been having a bunch of issues and codes and chasing down issues. I have replaced the MAF sensor, IAC, PCV valve, plugs, wires throttle body gasket and tps sensor so far but still having idle and rpm issues. It idles rough and while driving my rpms hang around 1900 unless I **** into neutral then they hit about 2800 before dropping down to 1200. I’m thinking vacuum issue but not sure codes I’m getting are P0171 P0174, and P0068 also does anyone know where this missing vacuum line would go? Top one goes to vacuum reservoir Thank you in advance

 

What did you replace IAC Valve with?

Needs to be a Motorcraft IAC Valve, 3rd party don't work

Vacuum leak test is very easy
Warm up engine and let it idle
Unplug the 2 wire connector on IAC Valve, it should close all the way
Idle should drop down to 500rpm or so, engine barely running, or engine may stall, either is GOOD it means no leaks

No, don't have a vacuum diagram for your year but should be one on your rad support with other info
Just cap that port for now

P0068 means your air flow data is not in-sync
The computer KNOWS its running a 3 LITER engine so it KNOWS how much air will be coming in at ANY RPM its just math
It uses the MAF sensor to determine the WEIGHT of the air coming in and the throttle sensor to determine the LOAD on the engine
So RPM + WEIGHT of air + throttle position = computers air/fuel ratio calculation
And something is OFF 1 of those 3 is out of balance with the other 2
This would set all 3 codes you mentioned

Since you have changed so many sensors, which do NOT fail by the way, it will be hard to determine what is wrong, a sensor can fail just really long odds that it does
Unless the new sensors are Motorcraft it will be harder still, some 3rd party sensor are fine to use, but not all, IAC Valve is a Control not a sensor, it must be motorcraft, even from a wrecking yard is better than new anything else
If you have the old Motorcraft sensors put them back on
Only sensors that wear out after 100k miles are the O2 sensors, just FYI

There is a large air tube between Air Filter/MAF sensor and the upper intake, that needs to be air tight, if not thats a Ported Vacuum leak, which can through off the air weight

 

Thank you. I am sure the IAC Is not a Motorcraft it think it is a Duralast so I my try that. I unplugged the little boot and plugged the main port and it seemed to steady the stationary idle and shuttering while driving but not the high idle while driving

 

My 171/174 codes went away when I replaced MAF sensor and all 4 o2 sensors. It was NOT cheap, easy, or fun but it ran better for a while until my radiator and head gaskets blew out 😬 hopefully those were unrelated issues though lol

 

Hello JASONNAIA,

I came across your post and noticed I have the same vacuum port on my 2004 Mazda B3000 DualSport 3.0l.

I'm not sure what the port was used for, it was capped off on my truck from the factory.

I used it to connect a analog vacuum gauge in my cab: