ive got a 97 f-150 4.6L!when i first start it up i can hear a lifter clattering for a few minutes than it quiets down.i changed the oil thinking that was the problem but still does it!any ideas on what it might be or how to stop it from doing that?

 

Change the lifters they are 5 bucks at rock auto. Can do it with head on and cam in.