Hey I have this issue with my 2011 as well. I am told by the dealership that it is the timing chain tensioner. I stopped going to the dealership when they tried to push this expensive repair on me. It can be better diagnosed by having someone listen to the area of the timing chain when starting the vehicle after it’s been sitting. My new mechanic says that the tensioner is controlled by oil pressure and that when your car sits over time, the tensioner releases (the longer it sits; the less tension remains). When you start your car it takes a second or two for the oil pressure to build up - but that clicking/rattling noise is the tensioner tightening back up (again, the longer it sat, the longer the ‘rattle’). Avoid giving it gas for those few seconds when you first start the engine and just let the pump/tensioner do their job. My mechanic assures me that everything is working as it should, it’s just not working as well as when the car was new. It takes a little bit more time for oil pressure to build and for everything to tighten up. I have had this problem now for over 5 years and other than being a bit noisy when it starts, my timing chain is still tight and I have no timing issues or engine miss-fires. But of course - ask your own mechanic about it and see what they say!
