Engine Ping

Usually a ping(pre-ignition/detonation) can be in direct relation to fuel quality, a timing issue, incorrect spark plugs, or malfunctioning EGR system. Has this been occurring for some time? Has it occurred over more than one tank of fuel? Has any repairs been performed recently that may be relative. And is there a check engine light? Typically, unless the concern is drastic, you don't have a ping at idle. Is it possible that this could be engine noise(top end).

That is what I would refer to as top end noise. I don't see much in the way of these vehicles pinging, the timingis electronically controlled, and by way of knock sensor(s), the ECM can fine tune it to reduce the occurrence of a ping. Internal engine noise can be a bit difficult to isolate accurately. It could be a faulty lifter that starts making noie as the oil viscosity thins as it warms. If you can develop a suspect side of the engine, you may be able to run it with the valve cover off, and see if applying pressure to a rocker arm can change it. This can be a messy ordeal as the pushrods are going to spit oil. If it is doing it consistently at idle, the spillage may be minimal as the speed is low. You might even be able to identify it without it running by depressing on the rockers. None should be easily depressed by hand, or have looseness. I believe that your motor may have roller type rockers, and are non adjustable.