Weird Humm Sound

Discussion in 'Other Auto Tech' started by Vaz88GT, Apr 11, 2012.


  1. Vaz88GT

    Vaz88GT Active Member

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    Hi all, my girlfriend has a 96 thunderbird lx 4.6 L Auto. And about last year we discovered a crack on the intake manifold, DOES NOT run into the block. It sprays coolant on the engine at high rpm's. Anyways..

    About 6 months ago the car will make a loud humming sound, and I mean LOUD. You can hear it inside when she pulls up. It seems to also do it more when you turn on the heat. Also sometimes when it happens, the car will maintain its speed. Without pushing on the gas it will drive itself, almost as if cruise control switched on.

    Anyways, you guys are great with mustangs, They are not too different, hoping you guys can help us out with her Thunderchicken! Thanks! :nice:
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  2. N8Dogg98

    N8Dogg98 Mustang Master

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    Do the RPMs hang high when it does this... somwhere around 1500-2000 RPMs? If so, I'd suspect the IAC motor.
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  3. Vaz88GT

    Vaz88GT Active Member

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    Yes it does, also it idles high too. She likes to give it gas and it will stop.
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  4. N8Dogg98

    N8Dogg98 Mustang Master

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    There's your answer then. Fix the IAC motor and when you do make sure you buy an OEM Ford replacement. The chinese aftermarket ones are junk. Also, get that f**king intake fixed for the christs sake.

    No clue what the humming could be, so perhaps you could try and describe it more. Is it simply the humm of the engine revving constantly at 1500-2000 RPMs?
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  5. Vaz88GT

    Vaz88GT Active Member

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    Thanks for your help :hail:

    Also we just haven't had the money to buy the part until recently.

    I will record a video of it happening, ill circle the car and the engine and let you hear it.
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  6. N8Dogg98

    N8Dogg98 Mustang Master

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    FWIW, you should be able to buy a replacement FRPP intake from Summit Racing for about $200. It is very easy to swap out, and there are many good write-ups on the internet for it. In fact, if you buy the 99+ PI intake with the necessary hardware for the swap you'll gain another 10-15 RWHP with the better design of the PI intake.
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  7. Vaz88GT

    Vaz88GT Active Member

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    I'll check it out, thanks again!
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