system too lean bank 1 and bank 2

Discussion in '1998 - 2011 Ford Ranger' started by Blake, Dec 31, 2021.

  1. Blake

    Blake New Member

    Some background: I have a 2006 Ford Ranger XLT with the 3.0 V6 with 75,500 miles

    I originally got the truck from a lot that picked it up for abandonment in Long Beach. The truck sat for around 5 years because of my cousin refusing to maintain and use the vehicle, but I needed a ride and already liked the way it looked.

    The problem is, I cannot get it past CA smog with a CEL (check engine light). I plugged in my OBDII and it spit out the codes P0171 and P0174 which translates to: system too lean bank 1 and 2

    I have researched the code and found that the MAF sensor and O2 sensors can cause the truck to give the codes, so I replaced them both with Bosche parts NOT motor craft. I also checked for leaks in the intake with starter and didn’t see a change in idle.

    The truck runs better warm than cold, but after a little bit of driving it sounds like it is sucking in air and maybe misfiring? I haven’t driven it far with the new parts (40 miles with the MAF and 20 miles with new O2 sensors). I keep taking It to my local graveyard to drive in fear of getting in an accident or being pulled over cause the tags are for 2016 so I can’t really open it up.

    Maybe I just need to let it get more miles with the new parts?

    I wanted to start my second semester of high school driving the truck because the thing is sick, and have been getting bent out of shape about not being able to drive the thing LOL.

    I’ve heard that a intake gasket leak is common on the 4.0s and could happen on a 3.0 so I might look into that, or one of the many vacuum hoses has failed?

    Any ideas would be greatly appreciated! Thanks!
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  3. OP

    Blake New Member

    update: i found out a very simple way to test for a leak. while the truck is idleing it should be around 750-1000 rpms. Let the truck get warm then walk to the engine bay and unplug the IAC (idle air control) sensor from the throttle body, if your truck drops to 500rpm or stalls then YOU DONT HAVE A LEAK. congrats! unless your like me and already redid all O2 sensors and maf sensor and now need to replace the fuel filter and injectors...

    the IAC is on on the intake manifold on V6 engines and the 2.3L engines from 2001 and up.
  4. RangerAl

    RangerAl Member

    Seem like you have some sort of leak. The best way to test for leak is "SMOKE" test, pumping smoke into your intake and see where it come out. If you look into Youtube, there should be all sort of homemade "smoker".

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