The knock is most likely a rod. If the noise is at about 2k rpms, and you can manipulate the noise with light throttle inputs then it's definately a rod. Also see if you can eliminate or change the noise by killing one injector at a time. I would drop the pan, pull the bad bearing, polish the crank with emery cloth, install a new correctly select fit sized bearing with a plastigage. If the oil clearance is too high, check to see if you can install a bearing with a higher select fit size.