Popping in air box?
I have a 2005 Taurus with 3.0 (u)
A couple weeks ago, I started hearing a faint popping sound under the hood. I opened the hood to investigate and noticed the sound was coming from inside the air box. I opened it, removed the filter and looked around. I found nothing in there that could be loose.
Next I started the car with the air box open. I traced the sound back into the plenum. I have no idea where it is coming from inside there. The sound keeps getting louder at different points. Doesn't matter it I'm sitting still or driving. Sometimes it just stops for a day or so and then starts again.
It was last serviced at Ford about 3 weeks prior. Oil change, plugs, wires, etc..
Other than the popping sound, it runs great. No miss of any kind. Just noise.
Can anyone point me into the right location of the possible cause?