i HAVE PERFORMED MANY REPAIRS ON THE 4.2 AND FROM EXPERIENCE i WOULD BE 100% SURE THAT IT IS A BEARING NOISE POSSIBLY A SPUN #1 ROD BEARING AND A POSSIBLY BENT #1 ROD THAT IS TAPPING AGAINST THE CRANK. I HAVE SEEN ABOUT 5 IN MY SHOP WHEN IW AS AT THE FORD DEAL... Login to read more.