high pitched whistling sound
 

Help!!!

Sometimes when idling there is a very high pitched whistling sound from the back of my engine...

I've tightened the intake circular clamps and it doesn't seem to help and they are tight, but if I wiggle the intake pipe to the manifold, the pitch changes so I'm pretty sure that this is an induction leak>

Sound familiar??

Hotshoe

Does it occur only when the engine is relatively cold?

Whistle while you work.
 

Yes sounds like an induction leak.

Get yourself a length of rubber hose, stick one end in your ear, then probe around the area with the other end. You will know when you find the leak by the sound.

Harvey.;)

two scenarios on an induction leak:

1. when I bought my car I gave a good look and never noticed until I pulled stuff off to change out the tranny that someone had bent over a portion of the rubber collars that go onto the throttle body. the bent over part was on the inner/lower side, and couldn't be seen by simple inspection. so, might want to pull the tubes just to make sure unless you're certain they were put on proper.

2. one of my kids just found a crack in the plastic intake pipes for a 93 ford probe. it can happen with heat & vibration.

The reason I asked about the engine temp is that lately I've been getting a lot of cars that whistle underhood when the IAC is open for cold idle speed-up.

intake whistle,
 

Beav,

100% correct, only when the car is cold, immediately after start up.

Seems to go away once its warm: normal? or should I do something about it?

Hotshoe

I'd recommend doing as the others mentioned and double check all the connections near the throttle body and snorkel tube. The problem nowadays is with every OEM using plastic snorkels and manifolds, etc. the noise of air moving through the induction system is more apparent than in older models and causes some concerns for owners unfamiliar with the difference. Some days it drives me crazy because I'll be chasing phantom air leaks myself when doing driveability diagnoses.

If you are convinced that everything's as it should be consider it o.k. to go.