After installing a CFM Large mouth intake manifold on my 06 powerstroke, I began to notice a sound similiar to feedback coming through a speaker. It is loudest when I am accelerating under load. A couple of times, I heard it right after I shut the engine down. I can't tell if it is coming from inside the truck or under the hood. My Pop says that it is pressure coming back through the intake. Could this be the same thing as the 'turbo fart' you mention? I have not lost any horsepower and everything seems mechanically sound. Has anyone else experienced this, or know what may be the cause?
'06 F350 Lariat
Silverline 4" Turbo Back Dual Exhaust
CFM+ Large Mouth Intake
19.5" American Force Classic Round Hole Wheels