watt4

thanks for the responses. I haven't had a chance to get another look at it-busy at work. I'll take another look at intake area, maybe I missed something the first time. I'll look at the throttle body too. It's a stock intake.

QuoteWarz Insurance

It has to be someone toward the beginning of the intake track. It sounds like it has an aftermarket intake, but if that is not the case then there has to be a leak somewhere.

watt4

Thought I'd post an update. Well I looked at all intake connections, and can't find anything loose or sloppy. I sprayed some throttle body cleaner around the throttle area, and did not detect any change in RPM. But while I was tinkering, I have noticed a slight change in the nature of the noise. It now sounds more like a metallic rattle, kind of like a bearing. I'm thinking alternator at this point. I've been reading other threads, and that seems to be a common problem. There's an excellent thread called "engine whistle", regarding this subject, posted by sincityfx4. Sorry, I'd post a link, but I haven't figured out how to do it yet. I'll keep you posted on the alternator, as soon as I can get to it. Kinda busy at work these days....

Idratherbediving

My 01 Super Crew started making a whistle noise last fall. It usually happens while I'm maintaining HWY speeds but I've heard it around 30 mph on occasion. It tends to cycle from quieter to louder without any change in rpm's or speed or throttle position (Holding constant speed). I can make it go away by accelerating. It will also get louder for a few seconds after I let off the gas and coast, then it will also go away.

I do have a K&N CAI and have checked and rechecked all the connections. It always has made a small whistle noise when letting off the accelerator (sounds like a diesel turbo and is explained in the K&N instruction book) and still does along with this new whistle.

I think my problem is in the vacume system, so for starters I plan on taking off my EGR valve and cleaning it.

Please keep posting. If we have the same prob I'd like to know how you fixed it.

watt4

no problem-but I haven't done anything more since my last post. It doesn't seem to be causing any performance problems, and I've been too busy to have a better look at it. Just from reading your comments I'd have to say that we have two different problems. Mine only makes the whistling noise when I give it throttle, and goes away as soon as I back off. Of note-something new I've noticed, the noise is definitely most noticeable between 45-50mph. It's also there, a little less, b/w 55-60, and less so at slower speeds. I don't really hear it faster than this, or slower. I am also hearing a metallic rattle sometimes, like a bearing. I don't know if it's related to the whistle. But as soon as I can get some time into it, I'll post again with an update.

watt4

by the way idratherbediving, did you install the cai yourself? I have a stock intake, and am considering upgrading eventually. If you installed it, have you noticed a significant increase in power? mpg? I am just now looking into it. Thanks for any comments.

Idratherbediving

I think your right about our problems not being the same but I'm not totally convinced I have an EGR problem. None of the "whistle noise" threads that are posted even mention the vacuum system or the EGR valve as a potential problem. But thanks for your posting, I like to learn as much as I can.

Installing my K&N FIPK was really easy. (And I'm no mechanic) I bought the FIPK without the heat shield.

When I first installed the FIPK I noticed a small increase in power but I've never noticed an increase in mileage.

I'm big on trying to increase gas mileage. My Haynes manual suggests cleaning or replacing the EGR valve may improve mileage. Although it also states that my OBD-II should detect any problems within the EGR System. I don't know if a dirty EGR valve is a problem. (Can you tell I’ve been reading about EGR valves?)

I’m considering getting an Edge programmer to increase my mileage.

Please keep posting ----

72404F150

IDRATHERBEDRIVING,

I have a '00 F150 5.4, my truck does the exact same thing. I havent noticed it at highway speeds yet, but noise has just recently started. The noise to me sounds somewhere between a whislte and a high pitched moan. I've also noticed that I can only duplicate the noise when the truck is under load, not free reving. Please post the EGR results. This noise is driving me crazy! Thanks.

Idratherbediving

72404F150

I'm going snowmobiling tomorrow so it might be a day or two before I post any results.

If you happen to learn anything please post it, I'd sure like to find a solution.

Idratherbediving

I tried to get my EGR valve off last night but I found out that I needed a 1 1/4 open end wrench to do it. So, I bought one today. I'll try to take it off again tonight or tomorrow morning.