Whistling trottle

[Cevigney]

When ever I hit the gas my 94 ext Whistles, granted if I do it right it sounds like a Turbo. And it is running better. but I can't help but think something is wrong.

Bad vacuum hoses?

 

[Iron Weasel]

A whistling sound is almost always a vacuum leak. If it's really high pitch, then it's an open vacuum port or missing / broken hose. The fun part is finding where it's coming from since you have the noise of the engine masking it.

 

[modified]

CoulD be a loose serpentine belt?

 

[Anime]

The whistling might be a loose vacuum cap or hose on the vacuum tree, located on the driver side at the rear of the upper intake manifold. You can either pull caps to see if any of them are dry and cracked, or sometimes just putting some armor all or something on them restores the rubber enough to seal. Replacing the caps is usually a better fix, and it's just a few bucks for a vacuum cap assortment at the parts store.

A serpentine belt that's loose will cause a lot more problems than a whistle.

Slick or slipping serpentine belts will just chirp though, as will tensioner or idler pulley bearings, though I suppose it would be possible for a bearing/pulley to vibrate at a high enough pitch to make it sound like a whistle.


The IAC valve can also give a whistling noise, especially the ones with a black filter cap on the side. I've got a stock cap without the filter, but it still whistles sometimes, although it's a low nervous whistle, and fairly obvious.

 

[saskman]

Mine was doing that and it was a split 90 degree elbow off the vacum tree on the intake. It was split on the bottom side so I just listened and poked and pulled at lines till I found it.

 

[malohnes]

A cracked/dry rotted grommet in my vacuum booster made the exact same sound...

 

[92/93on33s]

I have encountered a situation like this and the cat had exploded and was stuck in the exhaust and it made that sound. But I do agree with them too could be vacuum leak.

 

[rocco123]

Had a whistle on my son's jeep that i chased for 2 years. Ended up being the intake manifold gasket...after changing the throttle body, iac, vac hoses, tps, & egr.