[Build-It-Break-it]

I would start with engine oil level/pressure, Belt tensioner, or valve adjustment.

I had a 2013 g35 coupe that would do the same thing on initial start up. I did regular maintenence regularly but never oil level checks because I was being lazy and my wife was the driver of it. I thought it was the belt tensioner and started to tear the engine down but stopped about 1/4 of the way and thought "let me check the oil" . Well there was nothing on the dip stick. Topped it off and put it back together and no further problems. Turns out those cars burn oil easy. I sold it that month.

Id keep it simple and start with the easy to check items.