Engine Howling (replaced IAC)

[FloridaState]

Hey guys, I've got a problem here. My engine is making that howling noise (similar to the feedback noise you get sometimes on microphones) that happens every now and again. I was sitting in the parking lot waiting for class to start and I noticed it, so I turned off the AC and it stopped. Turned it back on, and it came back. I just recently got my AC fixed, could that be it?

Normally I would chalk this up to a bad IAC, but I just replaced the IAC about a year ago...could it really be bad already?

It seems to make the sound randomly, as I don't hear it every time I have the truck on. I'd just like to know if you guys think it's the IAC again before I go blow some money that I don't have on another one.

Any help is appreciated!

 

[jlsparky7]

A video would help. Maybe the ac compressor?

 

[FloridaState]

Hey sorry, I've been really busy, didn't mean to seem ungrateful for the response.

But anyway, it's hard to get a video of it because it only does it randomly, seemingly with no rhyme or reason. I'll try, but I don't know if I'll have any luck.

I really hope the AC compressor isn't already bad...it's been replaced 3 times already.

 

[justanother1]

Did you replace it with a genuine Ford IAC valve? If not, Id say this is your problem. I had the same issue on my wife's ex. I went to the local stealer and had to give the emission code to get the correct IAC valve.

 

[FloridaState]

Oh hai guys, almost forgot about this place :

Sorry for the lack of responses...been super busy with work and school. But no, I don't believe the IAC is Motorcraft. I finally got the dang video, though. I swear it's like my truck knew when I was video taping it, because as soon as I whipped out my phone, the howling instantly stopped.

The howling starts at around the :18 second mark. Sorry but this appears to be the best I can do.

 

[Turdle]

The IAC goes wooo!

 

[FloridaState]

The IAC goes wooo!

So that's what it is?

Great, there's another $100 I don't have. Is it something that MUST be replaced, or is it fine as long as I can deal with the noise?

 

[Turdle]

Try this.
Clean the IAC valve,You will see a plunger rod inside. Be sure to clean all the residue off it so it slides freely.
Then, replace the air filter with a good paper element and turn the idle set stop 1/2 turn counter clockwise.

The logic behind this is to change the air flow going through the IAC valve.

 

[FloridaState]

Try this.
Clean the IAC valve,You will see a plunger rod inside. Be sure to clean all the residue off it so it slides freely.
Then, replace the air filter with a good paper element and turn the idle set stop 1/2 turn counter clockwise.

The logic behind this is to change the air flow going through the IAC valve.

Whoa, you lost me. I literally have no idea what the underlined portion means lol. Are you talking about that little black cap on the IAC?