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Old 12-31-2007, 11:21 AM
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Join Date: Dec 2007
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Vehicle: 1998 Ford F150 4.6
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Question 98 4.6 vacuum leak?

When I'm at a complete stop and have all accessories turned off there is a loud whining noise coming from the middle of the dash. I'm guessing that it is actually coming from the engine compartment. Has anyone experienced this on their truck? It's a 98 4x4 with the 4.6. Could I have a vaccume leak somewhere and thats what the noise is?? If I put the engine in park is seems to go away but then it comes back when in drive and not moving. When the engine is under load. Any ideas??
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Old 12-31-2007, 10:52 PM
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Possible vacuum leak going to one of the actuators in the dash.
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Old 01-01-2008, 07:22 AM
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Turn the selector to "vent". Still here it?

If so - The 98 Vacuum lines plug-in is visible and easy to get at under the dash. if you look in the right spot . Sitting in the driving position about 4" above your right ankle to right is a plug-in with 4 or 5 different colored lines. Check that for leaks.
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Old 02-12-2008, 07:55 PM
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Well I took it in to the Ford dealership and they said the noise I'm hearing is normal and that it was coming from the IAC Valve. Normal my A$$. Nothin but crooks!
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Old 02-12-2008, 08:03 PM
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Do you have an after market intake? Well , IAC 's do make noises . But you said a "whine" - The don't whine that I know of.. I take that back , they do whine when its colder than sh^t out side lol.

When they do whine in that circumstance, it almost sounds just like a bad power steering pump lol .


Read This -

Bad IAC ???

Last edited by jbrew; 02-12-2008 at 08:11 PM.
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Old 02-12-2008, 08:25 PM
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Does the whine sound like this? -

http://s131.photobucket.com/albums/p...nt=snowfun.flv
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Old 02-12-2008, 09:02 PM
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No thank god. Mine is more of a whistling sound. Can hear it at a stop light inside the cab, but as soon as I give it gas, it goes away. :o And yes I do have an aftermarket intake.
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Old 02-12-2008, 09:10 PM
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My 97 had pinhole in the lines that run from the engine to just behind the battery. I found them by keeping the engine running and spraying the lined with a squart bottle. When the sound stopped for a second and returned I looked in that area.
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Old 02-12-2008, 09:47 PM
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Quote:
Originally Posted by 98f150guy
No thank god. Mine is more of a whistling sound. Can hear it at a stop light inside the cab, but as soon as I give it gas, it goes away. :o And yes I do have an aftermarket intake.

The dealership said it's the IAC . You do believe them right ?
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  #10  
Old 02-13-2008, 02:01 PM
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Quote:
Originally Posted by jbrew
Do you have an after market intake? Well , IAC 's do make noises . But you said a "whine" - The don't whine that I know of.. I take that back , they do whine when its colder than sh^t out side lol.

When they do whine in that circumstance, it almost sounds just like a bad power steering pump lol .


Read This -

Bad IAC ???

Sweeet, I have this noise and I think you are right about that....It only happens when its around 0'f ive noticed.
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Old 02-13-2008, 02:01 PM


 
 
 
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