Since it's been cold here in NJ the last few weeks, my 03 Exp 4.6l has developed an interesting sound. While driving at exactly 66 mph, I hear a very high pitched whine or whistle coming from somewhere up front. I tried an experiment to see if it is related to vehicle velocity cutting through the wind, or something in the engine. The noise is a "sharp" whine, not a flutter or vibration type sound. Almost like what you'd expect to hear from a high pitched tuning fork as opposed to a leaf caught in the fresh air intake, or a piece of plastic flapping in the wind. Hope that helps describe the sound. It is also not coming from feedback through the radio - checked that already.

What I found was, using cruise control, at 66 mph under no load (flat road, or going down hill) I hear the whine. Under load (going up hill), the noise goes away. I monitored the rpms closely and found that they did not change much from load to no load, but there was enough that I could feel the engine labor to go up hill a little.

So it seems like it is related to the engine, and not the body wind noise. I also noticed that it only occurs at 66 mph. go faster or slower, there is no noise.

Ok, last piece of the puzzle. I do have an AF1 intake - and I know the sounds it makes under cruise and load. However, I'm thinking that maybe some air is getting in somewhere at the connection to the TB or something like that.

I could use any ideas creative minds have to offer.

Thanks for helping...

PS - of course, the noise occurs at EXACTLY the speed at which I'd like to cruise to work. Couldn't happen at any other speed!

 

Do a quick search of the forums here, recently even, and you will notice that you are not alone. Some things to check are the IAC, if you have never cleaned it or replaced it, start there. Also check the vacuum lines for leaks. MY 2k does the same thing, but only in cold temps, I am going to replace the IAC soon (i.e. when I am not lazy and have the time). I believe that will take care of my problem. If you figure it out first let us know!

 

Not familiar with that (yep, I'm a noob). My mpg's have been off for a while too, in spite of the cold weather. My mechanic friend suggested I look for a vaccuum leak around the hoses going into the TB area. Wonder about that.

So, what is IAC, and what kind of term do I look for in the search. Just "whine"?

Sometimes I feel so silly trying to figure this stuff out. Never had this problem on my 71 Maveric straight six 3-on-the-floor. Now that was a car!

 

I just got my 01 Super Crew 2 days ago, soon as I left the lot I had a high frequency noise that I believe is coming from the speedo cluster. It comes and goes and it isn't coming from the speakers. I don't think it's a vacuum problem. I'll try it again tonight to see if it flucuates with the RPM's or change in speed. It's very annoying though. Please help..

 

IAC = Idle air control valve. It's attached to the back of the throttle body on my 2k, I think on the 4.6's it is attached to the sides of the TB. Search for whine, or rough idle, or engine noise....any of those should lead you to the discussions. Still can't find them let me know and I'll dig further for ya.

 

for the definition. Did a quick search = Wow! many of those posts could have been mine. Very consistent. You'd think Ford would have diagnosed this problem with so many precise descriptions.

some say it is the pcv valve freezing, some the alternator. Some even say the mirrors or the fog light recpticles.

Sounds like it is coming from the TB location which might be either the IAC (now that I know what that means) or the PCV. At least I have a place to hunt.

Now I need to find me a warm place to work on it... much more difficult task.

 

Your welcome, just let us know what you find so we can add it to the long list of fixes so that someone else later down the road solves their problem.

Fortunately my garage is heated, plenty of comfortable space to work on the truck with!

 

Well maybe I should just mosey on over to your garage

I will post results if/when I get a chance to look under neath

Thanks again,

 

My 2000 ,2002 ,2004 and now my 2005 all have done this and it's the cold air coming in thru the cabin filter.In all my cases no problem with temps. above -20 deg.or at lower speeds.The ford cold weather team is trying to fix last i heard so turn up the radio.

 

Maybe they accidently dropped a Corba motor in it

 

Where is this located and is it changeable?

 

Maybe it's a different problem. At least on my truck it is RPM dependent with the truck moving, If I am under load at say 55MPH the noise is there for a few seconds, but as soon as I let off the throttle OR give it more gas, it will go away.

 

That's what I tell everyone who asks about the whistle. I've had this problem for 2+ years now, can't figure it out. I've done the IAC replace after numerous cleanings, whistle remained. I changed the K&N thinking the crappy foam gasket was the culprit, nope, they had no problem giving me a new one due to that problem though, very cool. I changed the belt, PCV valve and tube, got rid of the clutch fan for e-fans, replaced the plugs and still it remains. It is ALOT more quiet than it was before, I hardly have it now, so it kinda fixed itself.

My next project is to replace the idler pulley and/or the tensioner pulley as someone suggested here before and that seemed to work.

 

Where is the cabin filter? Can it be changed or cleaned?