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  1. #1
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    Default High idle when rolling?

    For some reason my car suddenly started idling higher when in motion until completely coming to a stop. I dont even have to give it gas on flat ground to keep speed. Once I come to a COMPLETE stop for a couple of seconds it will jump back down to notmal idle speed.

    If I bump it in neutral while rolling it will hang at 2,000ish rpms, what part of the tune will delete the bump in idle (stall saver?) Id be happy if the IAC would stay at the same exact position no matter if im moving or sitting still.

  2. #2
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    Default

    My car does the exact same thing except mine is m6.

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  3. #3
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    Default

    The program increases the idle speed via raising IAC counts when the vehicle is moving. As RPM increases due to throttle position, the IAC opens more to control coast down when the throttle blades suddenly close. That's why it happens.... someone else will have to tell you how to alter that in the program. There are decel fuel cutoff (DFCO) tables, but I don't know if they also cover the IAC count increase.

    You may just have a problem with the IAC valve.

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  4. #4

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    Quote Originally Posted by Injuneer View Post

    You may just have a problem with the IAC valve.
    ^^^This, if it "Suddenly" started doing this, then its not in the tune...

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  6. #5
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    Default

    I was thinking that too but after stopping it goes back to normal. I'll try cleaning it but it's probably not gonna help.

  7. #6
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    Default

    Quote Originally Posted by Injuneer View Post
    The program increases the idle speed via raising IAC counts when the vehicle is moving. As RPM increases due to throttle position, the IAC opens more to control coast down when the throttle blades suddenly close. That's why it happens.... someone else will have to tell you how to alter that in the program. There are decel fuel cutoff (DFCO) tables, but I don't know if they also cover the IAC count increase.

    You may just have a problem with the IAC valve.
    throttle follower iac offset table and a few others change that. there's also a park vs drive or gear follower table that sets the rpm for 0 throttle coast to stop, it's to help your power steering

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  9. #7

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    There is an IAC throttle follower that can be adjusted, but again if it was in the tune it would have done this from the start, so not sure whats going on, check for any unmetered incoming air?

  10. #8
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    Default

    Probably the IAC like you said, it "fixed itself" for now lol

  11. #9
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    Default

    Well drove the car again, I guess it only does this when its cold outside but when I crank the car cold the idle is fine, once I put it in gear it is fine. BUT once I let off the brake and let the car move a few MPH the rpms come way up and the car will stay around 1800-2000rpms untill the engine warms up AND I have to come to a COMPLETE stop for about 5 seconds in neutral before the idle will return to normal. Then after I put it in gear and drive it is completely fine as long as the engine is warm....

    SO I guess Ill check my tune again and see if I messed with something but not sure what to look at as far as cold idle when in motion?

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