Same here, if you let off the gas, the noise goes away.

 

In that case, it just about has to be in the intake tract, right? What would be common between a truck with an OE intake and one w/ the Roushcharger? It looks like the throttle body is reused, and it's the only component that seems common in all of these instances everyone has listed.

Is there some feature in the throttle body that could whistle given the right air density and velocity? If the whistle is there, you may be SOL for ever eliminating it.

You about need a temperature and humidity controlled room with a dyno to really get your arms around this one.

 

I'm not entirely sure it's the intake. I have the complete Airraid MIT intake system and it does it. Sounds like some of the posters have the stock intake system and a co-worker has a 04 FX4 with the scaled down Airraid jr. intake system and it does it.

I had a whistle through the intake when I originally had the K&N Intake system installed, as it has a throttle spacer that relocates the throttle body up a bit to increase the size of the plenum. According to K&N this is a known issue and they credited me my money back because of it. The sound is also different, as it happens at different levels and was pretty much constant regardless of RPM range.

The sound definitely goes away in warmer weather and only occurs, at least on mine, when the temp falls below -8 degrees C, 1800 to 2000 RPM and when the vehicle is in motion.

Doug

 

I have the same problem, loud squealing noise from powersteering pump in morning when cold. Also when driving down highway or interstate loud whistling/squealing noise. Brought it to dealer today and didnt make any noises for mechanic (of course). Basically he told me I was an idiot and not to worry about it. I think it is NOT normal! A 2005 F150 with 14000 miles it should make NO noises of this volume reguardless of tempuature. Very frustrated and annoyed!

 

I have a 2004 FX4 5.4 engine, I live in Northern, MN where it has been getting down to -30-40 below F. My truck does the same thing. I had my alternator changed the first winter I had the truck and the sound went away. However, the sound came back with this recent cold snap. I actually had another, "redesigned" alternator put in today and so far so good. The dealer did not have a reason as to why the alternators whistle/squeal when cold?? I will keep you all posted if this seems to work. It is supposed to be -15-20 tonight so it will be tested in the morning.

 

Have 2004 Fx4 Screw And Also Does This,only Does When Like 20 Degrees Or Colder Also In Mn.
Had Read On Other Posts Last Year About Same Thing And Said It Was The Cooling Fan In The Transmission?
As Long As I Keep It Below 2000 Rpm Til Gets Warm Usually Pretty Good.

 

I park inside, so the engine is at around 40 degrees when I leave in the morning, the squeal starts right away, so in my case, I feel its the air intake, or someone else said they hada PVC valve that was the problem. In any case I have not found my "cold air whistle" yet.

 

I guess the only good thing is that we are heading into spring and the noise will be gone come April for another year...


Doug

 

Same thing....bone stock 5.4 in a 2005....dealer supposedly can't replicate it.

 

Mine just did this for the first time yesterday but I think this is the coldest its been since I bought the truck (around 9 degrees in the morning) I have to do some more checking on this, it definetly sounds like air flow not a part I think.

 

Just had this happen to me this morning. Temp in the garage: 23F Temp outside 12F.

I noticed the squeal comes on around 1600rpm. After 20 minutes of driving it went away. I thought I had noticed it once or twice before, but this was the 1st time the noise consistantly repeated itself until 20 minutes of driving. It is un-nerving.

 

well...i'm supprised that someone else hasn't already suggested it but, rumour has it that its your idle air control. a ford famous it seems, i've got the same problem in an '02 s'crew 4.6l. in the 97-03 forum there's a thread about it with pictures...guys have cleaned/replaced it and the noise goes away...for me...it just drowns out the wife....

 

Same whitsling noice here. Throttle position sensative. I can make it whistle by modulating the throttle ever so slightly at about 34 mph with a 3.70 rear end, 4.2L engine, '04 F-150. Previous bulletins that I've read referenced the idle-air bypass flow circuit, specifically the bent nylon hose, to be replaced in the 5.4L engine with a nipple/hose assembly kit #2L1Z-9W548-AA.

I don't know if any of this information is correct as I have not been in for my next oil change. No driveability problems, I think it is merely an air hose or valve problem, possibly connected to age and temperature.

Never heard the noise until this January with 24,000 miles. Later Dudes.

 

Today the temperature reached 20-25 degrees F. and there was no noise. Previously there was. Others have said this means it could be the alternator (cold temperature-whistles, warm temperature-everything sounds normal). Any thoughts/comments?

 

I don't think that rules out anything in particular. If it's an alternator whistle, the bearings must be happier with the warmer temps. If it's an intake whistle, the warmer air temp has reduced the air density and changed the air flow dynamics or something else to eliminate the whistle.

It's still a mystery.