Status? I am having the same issue, 2000 Sahara 4.0L with K&N cold-air intake. The cold air has been installed over 3 years, the "whistling" sound only recently started. I'm pulling my hair out trying to identify it. Mechanic friends say doubtful clutch related. Water pump, fan clutch, and idler pulley 6 months ago new. Have not replaced tensioner pulley.... yet, but I was starting to lean towards that when I came across this thread.