Hello everyone. I have a 2009 Forester that pings under light to moderate acceleration when pulling away from a stop sign or driving between 20 to 40 MPH and maintaing speed on slight hills and is audible with the windows either open or closed. My Forester has only 8500 miles on it and I have always used "name brand" gasoline from various stations. I took it to the dealer today and was told that this is a common issue with this type of engine because of the cylinder layout/orientation. I personally feel that this is a bunch of bull___. I feel that with modern day electrical advanced timing and knock sensors this should be a thing of the past and that "ping" or "knock" is really detonation and not a good thing to have happening inside my engine. Anybody have any comments? Thanks for any help.