Infamous check engine lights

[Olsin6]

Never had any problem with my truck until now. Started it today and noticed my check engine light was on when I was driving to work. Buddy of mine has a Superchip programmer, so he plugged it in and read my codes for me.

Codes:
P0171 - Sys too lean (Bank1)
P0174 - Sys too lean (Bank2)

I read a lot of controversial stuff about what actually solves it because people tend to replace 3-4 things at a time. Most of what I see comes to the PCV hose/valve itself. Anyone had these codes and able to narrow it down to exactly what it was?

Thanks.

2003 Ford Ranger 3.0 V6 Flex Fuel

 

[Earl43P]

Pretty common for the 3.0 PCV 90 degree elbow to collapse/crack/leak.

You would notice that the idle seems to hunt.

If you spray that area with something combustible, the idle should raise, confirming the suction leak site. Some use an unlit propane torch, carb cleaner, etc.

 

[Colin]

Codes:
P0171 - Sys too lean (Bank1)
P0174 - Sys too lean (Bank2)

Those codes mean your o2 sensors are no longer working properly.

 

[Earl43P]

Those codes mean your o2 sensors are no longer working properly.

^ It's THAT kind of thinking that causes a lot of good parts to get replaced for no good reason.

http://oldfuelinjection.com/?p=31

 

[Colin]

^ It's THAT kind of thinking that causes a lot of good parts to get replaced for no good reason.

Well sorry to burst your bubble but that's exactly what was wrong on my truck. I had those codes, looked on the diagnostics computer and saw that both o2 sensors were not cycling fast enough. I replaced both sensors, which are fairly inexpensive, and they now cycle properly, I dont have any codes, and the engine runs a hell of alot better.

Thank you come again.

 

[locovaca]

Well sorry to burst your bubble but that's exactly what was wrong on my truck. I had those codes, looked on the diagnostics computer and saw that both o2 sensors were not cycling fast enough. I replaced both sensors, which are fairly inexpensive, and they now cycle properly, I dont have any codes, and the engine runs a hell of alot better.

Thank you come again.

You were one of the rare cases that both O2 sensors go out at the same time. A vacuum leak is far more likely than that happening, AND it's free to check for instead of plunking down $100 on a pair of sensors.

 

[Colin]

Well obviously you check for vacuum leaks before you start replacing parts. That's trouble-shooting 101.

 

[adsm08]

If his scanner can do live data there is an easy check to see if it is actually an air leak, or if something else is causing the issue.

View and write down the short and long fuel trims for both banks at hot idle and at 3500 RPM. Add the two together (short + long bank 1 and then same on bank 2 for idle and then the same for 3500 RPM) then subtract those two numbers on each bank. If result comes out at anything less than 15, you don't have an air leak.