For a long time at cold temps my 01 with 191k on it at cold start up I would get one lifter I guess it is that made the little rattle sound. It went away really quick. Now it seems that more than one are doing it now. After about a minute or so the sounds go away and the motor sounds just fine. Should I be concerned about this> That more than once is making noises now? It now almost sounds like a diesel at start up.