I have been chasing a sound for months now that sounds like my truck is moaning upon light acceleration. I think I found the cause. I took my entire stock intake off and I noticed on the bottom side of the air filter tray there was a 1/2 inch gap where the foam gasket was at one time but is now deteriorated and gone. I could see the filter plainly through this gap. Well I got to thinking that possibly my truck was gulping air and making the sound.....turns out I think that was the issue. I used foam to block the hole and i have not heard the sound in a week now. I recommend everyone checking that under side of their filter tray for this gap where the foam has rotted away.