2 Answers

Get a dowel at least half inch in diameter about 24 inches long . Start engine ,Put the end of dowel on valve cover touch the other end to your ear ,if the problem is in the valves it will be very clear . Find a clear route to the timing chain cover for the dowel and repeat the process of listening . keep hands and the dowel clear of fan and all belts ,dont be a idiot and launch the dowel thru your skull.The noise from a malfunction will be very clear when doing this ,then at least you know what part of the engine to open up. This is a shade tree mechanic trick works well

First and foremost find a good honest mechanic which I know is hard to find, but my best guess is that the valves need adjusting or replacing not sure?