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Codes for lean Lt & Rt banks

Discussion in 'Ford Trucks' started by MickiRig1, Jan 21, 2006.

  1. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    I get codes for left & right banks running lean on an OBD II system 3.8 - 6cyl.
    They lit the engine light and this is the only codes that come up.
    It has new spark plugs,all filters replaced all connections are good.
    It has 40k on it.The repair manual is useless,I have not had time to go to the library to look at a better look.
    Any ideas?

    CARDOCTOR PlowSite.com Addict
    Messages: 1,304

    need more info make model yr
    sound like a dirty maf sensor or fuel issue

  3. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    It's a 2000 Windstar 3.8.
    I inspected the MAF sensor and all the ducting it's clean,has a 6 mon old air filter which is also clean. New fuel filter,PVC,idle air control and spark plugs.
    I know it's not a plow truck but Ford tends to use the same systems
  4. JMR

    JMR Senior Member
    Messages: 567

    I would guess the two codes you are getting are P0171 & P0174. With out seeing the fuel trim numbers all I can do is guess. The two most common failures we see through the shop with this engine is 1) a vac. leak at the pressure regulator, but the most common problem is 2) a leak at the mid & upper intake gaskets. The left valve cover should also be replace when doing this repair. It is updated per a TSB. I will see if I can find the TSB.
  5. RYDER

    RYDER Senior Member
    Messages: 281

    It might be the o2 sensor.
  6. JMR

    JMR Senior Member
    Messages: 567

    Here is one of the TSB's the other is too large to attach, but basically repeats this one and covers replacement of the intake gaskets and a reflash of the PCM if necessary.

    Attached Files:

  7. Robhollar

    Robhollar Senior Member
    Messages: 766

    I doubt both o2 sensors went out at the same time. I agree it sounds like there a vac leak, or a bad coolant temp sensor. Best thing to do is find someone with a scanner.....Rob
  8. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    My thoughts are a bad intake or engine temp sensor. Without buying a $150 scanner I am in the dark! It's one of the things that the computer does not monitor.
  9. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    My Wife bought it with one of those extended warranties on it. I am going to read it and see what it covers.But first she has to find it!