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Lock-up intermittent at highway speeds...

This is a discussion on Lock-up intermittent at highway speeds... within the Automatic Transmission forums, part of the Drivetrain category; ...but seems to be fine at lower speeds. Took my car for a nice highway drive today, but noticed that ...

  1. #1
    TunedByFrost supporter rel3rd's Avatar
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    Question Lock-up intermittent at highway speeds...

    ...but seems to be fine at lower speeds.

    Took my car for a nice highway drive today, but noticed that it wasn't "holding" in lockup when at 65-80mph and at light throttle. At 45-55mph it seems to work, and hold, in lockup normally.

    When it would lockup, it might stay locked up for a few minutes or so, then for whatever reason, unlock and stay unlocked for several minutes. This was on flat road at steady speeds.

    It acted like this when I first installed camshaft, due to misfire code, but I get no codes. Back then, problem was also very intermittent and pretty much locked or unlocked whenever it damn well pleased...After tuning, it was fine until recently, with today being very noticeable. FWIW, car shifts the same as it ever has, and I notice no other things different when driving.

    Is it possible that it still needs tweaking of the misfire tables?

    Does ambient temperature have anything to do with this?

    It seems that it has only done this since it has gotten cold out.

    Any ideas?
    2002 Silverado Z71 ECSB HPTuners tuned by yours truly
    2000 Pontiac Trans Am WS6 6.0, 4L80E, Rear mount Turbo, etc...
    webpage: http://www.fquick.com/rel3rd/

  2. #2
    Member performabuilt's Avatar
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    I would say raise the engine missfire threshold to max and you should be fine in most cases

  3. #3
    TunedByFrost supporter rel3rd's Avatar
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    Thanks.

  4. #4
    Personally I think it may be in Jeff's tuning. He can extract a nice running engine from a radical setup and make it put down some power, but I've had all sorts of problems with my lockup working properly with his tune. The lockup worked great with "another local shops" tuning, but the car ran like ass. Been back to touch up the tune several times, still not fixed. New trans and converter - same exact issues. I'll be getting a FAST 90/90 in the springtime, and when I have my tune touched up again, I'm really going to put an emphasis on getting it right!

    I have noticed that right after a hard WOT blast when decelerating back to normal highways speeds it locks right up no problem, and holds for several minutes. Then it gets a mind of it's own

    Edit: If you find a solution to this (even though your engine and converter are different) PLEASE let me know what you found!
    Last edited by Marc 85Z28; 01-16-2008 at 12:53 PM.

  5. #5
    TunedByFrost supporter rel3rd's Avatar
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    Quote Originally Posted by Marc 85Z28 View Post
    Personally I think it may be in Jeff's tuning. He can extract a nice running engine from a radical setup and make it put down some power, but I've had all sorts of problems with my lockup working properly with his tune. The lockup worked great with "another local shops" tuning, but the car ran like ass. Been back to touch up the tune several times, still not fixed. New trans and converter - same exact issues. I'll be getting a FAST 90/90 in the springtime, and when I have my tune touched up again, I'm really going to put an emphasis on getting it right!

    I have noticed that right after a hard WOT blast when decelerating back to normal highways speeds it locks right up no problem, and holds for several minutes. Then it gets a mind of it's own

    Edit: If you find a solution to this (even though your engine and converter are different) PLEASE let me know what you found!
    Still haven't gotten back to PSI, but wanted to keep you all up to date.

  6. #6
    TunedByFrost supporter rel3rd's Avatar
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    Stopped by yesterday after work. Of course with the tuner in the passenger seat, and his laptop hooked to the car, we drove around for about 20 minutes and it worked flawlessly, LOL....

    Anyway, he still made some changes in the misfire tables and car has not acted up yet...I guess for whatever reason, the settings were slightly more sensitive, or otherwise different, since the ambient temperatures got much colder than when it was originally tuned.

  7. #7
    TunedByFrost supporter rel3rd's Avatar
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    Thumbs up

    still working great!

    Thanks PSI !

  8. #8
    TunedbyFrost.com Tuner Frost's Avatar
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    Quote Originally Posted by rel3rd View Post
    still working great!

    Thanks PSI !

    I have never heard a bad word spoken about Jeff or PSI. He is the only tuner that I have never met and have had the most limited online conversations with but would not hesitate to recommend for people to go see him. I have redone tunes from tuners all around, but never one of his cars. Glad to hear you got your issue sorted out, the car is much more enjoyable when we don't carry that mental stress from knowing something isn't exactly right

  9. #9
    TunedByFrost supporter rel3rd's Avatar
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    Thumbs up

    Quote Originally Posted by Frost View Post
    I have never heard a bad word spoken about Jeff or PSI. He is the only tuner that I have never met and have had the most limited online conversations with but would not hesitate to recommend for people to go see him. I have redone tunes from tuners all around, but never one of his cars. Glad to hear you got your issue sorted out, the car is much more enjoyable when we don't carry that mental stress from knowing something isn't exactly right
    couldn't agree more

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