Boost at high idle with a whistle.

[CircleH]

First I am glad I found this site. I asked a question on another forum about an isx and was quickly told Rawze. I bought a 2016 t880 recently. I am a farmer and my trucks only work about six months of the year. It has a 1sx15 450hp. I bought it with fairings on it and have been ripping them off and turning it into what I need. I have started it a dozen times to build air without driving it. Yesterday I drove it a short distance no load like three miles 20mph no trailer. When I parked it the idle went from 700 to 760 and I can hear a whistle. Is this normal? I took it for a drive today, drove it at normal road speeds for 40 minutes at operating temperature. Went to park it and it idled up to 760 and increased the best again. Showing a few pounds, like three on the boost gauge. This is my first emissions truck. Did I break it already? Is something stuck or a sensor bad? Any help would be greatly appreciated. Thanks