whistle from engine

[ontarioeddie]

Here goes. My 2004 with the 5.4 gives out a high pitched whistle from the engine in cold weather 30 degrees F or colder. The whistle sound gets higher with acceration and goes away sometimes. My 2004 F150 did this as well but it had a 4.6. Any ideas.

 

[AvroAero]

Check the aux lines on the intake. One goes to the valve cover and the other to the throttle body. Make sure they're not off

 

[XLTman]

Mine 98 does that too i will have to take a look at it

 

[bubbadabulldawg]

It is an intake manifold leak you might even smell something sweet every now and then it is antifreeze leaking and burning off on the engine.

My 03 has the same engine which is still under the 60 day warranty has developed it and is getting it repaired this Monday 12/17 along with the limited slip diffs, driver door window for scraping and scratching when opening and closing and also the front pass window switch, and I will also be mentioning the wind noise coming through both of the front door seals while driving down the highway and the wind is blowing (the sound is like when you hold a blade of grass between your fingers and blow accross it). Thank you Ford! The dealership is going to hate me before this warranty is up every day the truck is in the dealerships possession I get a day added back to the warranty to cover for lost of time and also supply me with a rental!