i have an 01 2.7l. i pretty much rebuilt the engine on it, new main bearing,rings,warter pump,oil pump, valve job. now that i took it apart for the second time, it seems to tap for a minute or so before it runs smooth. sometimes its just a couple of seconds and its gone again with no noise. does anyone suggest anything it could be. i thought maybe the lifters could be getting stuck but i remove the cap for the oil when its tapping and put my ear to it and it sounds good. doesn't sound like its in there but maybe echoing in the plenum