Horrible whistling noise coming from behind upper plenum, I think.

2002 FORD MUSTANG
130,000 MILES • 4.6L • V8 • RWD • MANUAL
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TEXASSTANG
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I have a 2002 Mustang GT and it is making an extremely loud high pitched noise noise near the intake manifold. I am throwing the following codes P1506, P0171, P0174, P0316, P0307, and sometimes P0303 comes and goes. I thought it was the IAC valve so I replaced it but nothing. Then I checked the vacuum lines and added some hose clamps where needed and teflon tape where needed, and still nothing. Lastly, I sprayed WD-40 around the vacuum lines to see if there was a change in rpms but nothing again. Please someone help me. I can post a video of the noise if it helps.
Dec 19, 2015 at 2:59 PM
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WRENCHTECH
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You have a bad vacuum leak that you are going to have to pinpoint. It's usually one of the large rubber connectors connected to the manifold. They suck a hole inward when the engine is running and that hole closes when the engine is shut off.
Dec 19, 2015 at 7:29 PM
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TEXASSTANG
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https://www.youtube.com/watch?v=-EuFK-P5kz4&feature=youtu.be
Dec 21, 2015 at 4:07 PM
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WRENCHTECH
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If you can't find it visually you will have to do a smoke test on the intake.
Dec 21, 2015 at 4:24 PM