Turbo Spooling up at Idle

[Golfnut]

I've some of my ISX questions on here over the past 6 weeks and need some more info. Since harvest has finished I've done a handful of things to my truck but have not needed to used it. i've replaced the IMAP and Delta-P sensors, rebuilt the fuel pump and installed an Amsoil Bypass oil filter. The truck is an ISX CM2350. I also had one of the great forum members here install a new calibration file upping the HP and torque from 450/1650 to 500/1850. The CPL on the engine is 3937 and the new file is for 3938.

I've moved the truck around the shop a few times since the cal file upgrade and notice that when the truck is idling the turbo sounds like its spooling up. If I bump the idle to 1030 it turbo quits doing it. It also slows down some after the engine is warmed up. Also, the fuel used when idling says its 1.6-1.7 gal/hr when idling 700 rpm and it drops to 1 gal/hr at 1030 rpm according to the trip computer. I've sprayed soapy water on all the fittings when its running and don't see any leaks.

Is this simply a function of the new calibration file? A result of the new sensors? Or a problem?