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Discussion Starter · #1 ·
Ok, so I was in the drive thru the other night at the good old MickyD's......and I was in park waiting in line, and I revved the engine maybe 300-500 rpms....and I heard what sounded like a very faint whistling noise....but when I let off the pedal, it lowered it's pitch and blended with the engine....but when I revved it again like that, the pitch of the whistle climbed, and then fell with the pedal released....Now I'm wondering....could this be a sign I have a leak in my intake somehwere or somethin? If that's what it sounds like, is there any spots on S-10's that may be prone to act up like this that I might wanna check? Any input will be most appreciated.....

I mean, I don't wanna use the old soap and water trick and get water in my intake.....but I dunno....any theories? Thank you!!!
 

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Discussion Starter · #3 ·
yeah I have an aftermarket intake....and it makes me feel better I'm not alone....but I still worry because I never noticed this whistle before...I'm wondering if I haven't maybe developed a leak?
 

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ΜΟΛΩΝ ΛΑΒ&
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mine also has a slight whistle to it...But if this is a new development I would deffinately check for Vac leaks
 

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Got Fuel Rails?
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Around the intake manifold. And the vac hoses. There are 3 main ones. The pcv, the brake booster, and the one that goes into the fender to the vac resevoir. Also, the base of the throttle body.
 

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i also have this once in awile, i have a k&n so thats probly what it is
 

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the youngest has been
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my truck was wining and sounded supercharged, i got out my carb cleaner and started checking for vac leaks it turned out to be a bad tbi to intake gasket

a quick change fixed it right up
 

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limeade
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I had this and it turned out my battery had 2 dead cells and my alternator was working overtime so it was whistling. Might wanna check them too.
 

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Discussion Starter · #12 ·
alright....well, my battery isn't putting out what it should at idle, and my alternator is only pushin out like half the amps it should....I dunno why either....I don't know what to do to fix this and I don't know what's causing it;....it's been a persistent problem for almost a year now, and basically what's happening is is that if my battery and alternator were humans....it's like it's getting stabbed and dying a slow painful death....I dunno what's goin on....
 

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Breakin shit
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my 99 blazer was doing this last week, The idler pulley between the A/C comp and alternator seized and trashed the belt shortly after the noise started
 

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it looks stock.. kinda..
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Sounds to me like you guys might be hearing the IAC valve. If I stand on it, and then back out I can hear the IAC let out a whistle as the computer closes off the IAC bypass.

Teeleton
 

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Discussion Starter · #16 ·
hmm, I dunno though, it sounds like it might be ok according to you guys....but the difference is when I get on my throttle, even slight revs of only up to 500pms more than idle...I can hear it get louder but when I get off, it settles....so mine is there when I get on it, not when I'm letting off....this is wierd guys, lol....and what exactly is an IAC valve?
 

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it looks stock.. kinda..
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It's the idle air control motor in your throttle body. Basically, it's how the computer controls the idle, since it can't exactly step on the gas for you. It opens a valve to let air leak past the throttle blade instead of actually moving the throttle blade itself. When it does this, often times it will whistle. You can unplug it and the engine will run fine. If your whistling goes away, then that's what it is.

Teeleton
 

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Discussion Starter · #18 ·
Alright, Thank you everyone!!!! Huge help, when I get back to my garage I'll check it out. I'm currently in phoenix right now, but I get back tomorrow and I'll check it out and let everyone know if these ideas cure my fears...lol, later!!!
 

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its your intake if you have an aftermarket intake, its the sound of the air rushing around the throttle blades. if you drill a tiny hole through the throttle blade it will go away. but i like the whistle
 

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Molon Labe
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4x4zr2GA said:
its your intake if you have an aftermarket intake, its the sound of the air rushing around the throttle blades. if you drill a tiny hole through the throttle blade it will go away. but i like the whistle
Wouldn't that mess up your idle?
 
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