New to me '15 Cascadia DD13, parked idle at 600rpm (seems low?) increases to 900rpm when clutch is pushed in. Can not increase rpm with foot throttle UNLESS clutch is pushed in, regardless of whether or not park brake is set. Seems to run ok on the road, if not a little 'surgy' if thats a word. Was an ex JB Hunt truck, had a local shop step up the rpm/speed limiters to 2000 rpm.