Truck is an 01 Expedition 4.6 with 120,000 miles. Runs good but makes a lot of noise! I've heard it described as a humming noise but it sounds more like a honking noise on mine since I have an aftermarket intake. I tried cleaning the IAC valve, didn't help. Ponied up the $50 and replaced it, still didn't help. It used to go away when I gave it throttle but now it does it constantly. If I unplug the electrical connection to the valve it stops. I'm reading a steady 13VDC from the connector. What am I missing? Any ideas on what else could cause this would be great!

 

Just thought of something. Could it possibly be another bad IAC valve. I got it at Azone. The Ford store wanted $170 for one!

 

Did you delete your IAC baffle when you install the CAI?

 

What baffle? The intake has been on there for years. I don't remember anything about a baffle.

 

The baffle is the tomato paste can size inline baffle that runs on the hose from the IAC to the air intake right before the throttle body, If yours is in there , i have heard of after market IACs causing this, I went with an oem IAC with my spectre CAI, theres a slight hum but i can only hear it if I have my ear to the filter