Near stall when decelarating

Discussion in 'V8 Discussion' started by GEN 3 SHO FAN, Aug 20, 2019.

  1. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    I observed recently that when I decelerate with the car, the rpm can goes to 200 rpm. The car doesn't stall (since now) but itsn't normal.

    Can air leaks on intake could do this king of thing ? (If fuel pressure drop but the air ratio stay high.) I still have some misfires on idle.

    Or it's the IAC valve that is going away. Not opening as fast as it should do.

    Thanks for the help,
     
  2. gamefanatic

    gamefanatic SHO Member

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    IAC would be my first guess. Not uncommon that it would not respond fast enough and choke it a bit before recovering. Wouldn't be noticable as much on acceleration.
     
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  3. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    Ok, I will try another used one. Thanks.
     
  4. stephen newberg

    stephen newberg Moderator Staff Member

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    I agree, it sounds like IAC.

    pax, smn
     
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  5. gamefanatic

    gamefanatic SHO Member

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    I have a few, but I think they should be still available.
     
  6. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    I'm running the original one which I cleaned last summer (throttle body cleaner + cure pipe). It seems that cleaning them don't do the trick for long. I have 1 or 2 used spares from some V6 2.5L. I will check this in the next days.

    Nimz123 also spoke about a trick give more headroom (play) to the valve to help prevent stall/choke... I'm wondering if it will help too. (For 96 year, we have a TSB about stalling when decelerating. The only solution found by Ford was to reprogram the ECM...)
     
  7. stephen newberg

    stephen newberg Moderator Staff Member

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    When you clean them, you have to be really gentle. If you can replace with new, its a better idea, as they are not (well, did not used to be) expensive.

    pax, smn
     
  8. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    I changed my IAC valve and it did trick. No more rpm falling when decelerating. It was an used one from a 2.5L which wasn't good, even cleaned...

    Thanks Stephen and Game fanatic,
     
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  9. stephen newberg

    stephen newberg Moderator Staff Member

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    Excellent news. It is surprising how often the IAC causes some of these hard to track problems.

    pax, smn
     
  10. patrick hubbard

    patrick hubbard Member

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    Mine does this some times
     

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