2009 Wrangler unlimited sahara 4wd, whistling / squealing when accelerating at 2000 rpm. Will not do it any other time. Have replaced idler pulley, tensioner and pulley, serpentine belt, air raid cold air intake filter. Tightened throttle body spacer, checked and tightened hoses. ensured torque specs on tensioner and idler pulley. and still get a whistling noise from engine bay at 2000 rpms. all fluids topped off. No steering issues and alternator working properly. Any other ideas of where this whistling or squealing is coming from? Thanks in advance for all the help.