Hello a little background first. I have a 2005 f150 supercrew 4wd 5.4. It has 267,000 miles with no problems yet. Well I started hearing randomly a. . for lack of a better word a "fart" noise when I start throttle tip in at 0mph taking off from a stop. I know what cam noise is, cat converter rattle etc. The truck is in 2wd im sure but at 800 rpm for about 1-2 seconds my truck farts from under the dash. Its a very low brrrrrrrrt the second you touch the gas. sometimes in neutral i can hold it right there and the noise will keep doing it. It sounds like its under my dash. Has anyone had a truck do this? Its very annoying because people always ask what its doing.

 

found it! the air inlet tube has that rubber grommet on it, well the grommet slid back and the noise was radiating throught the truck! awsome!