[2008 CTS 3.6 DI] Engine light is on code P0017. Could just be a sensor issue, but I know this code can also relate to an issue in the crank/cam or timing chain and tensioner. I have been noticing a whooping/thumping noise when starting the car cold. It will happen about ten seconds after the car starts and only a couple of times (thump thump, pause, thump thump) and then the sound goes away and will not happen if the car is being restarted soon after it was turned off. Is this sound related to the check engine light or something else entirely?