Hear a loud hissing noise when RPM hits 2, and turbo psi goes up help

Boost is good, what else could it be? checked trouble code says that I have a bad EGR valve..??? could that be the reason for the hissing sound I hear in cab of truck

Fix EGR!! Might find helpful vid on YouTube... Take a look at boost tubes also, if boost is ok they should be ok! .. Worth a look... *Suspect EGR!*

Thanks will look into that...