One problem related to engine funny noise has been reported for the 2013 Porsche Cayenne. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2013 Porsche Cayenne based on all problems reported for the 2013 Cayenne.
Purchased a 2013 Cayenne Porsche gts with 67k miles on it. Noticed a kind of thumping sound when accelerating, usually appearing at 3k rpms. Vehicle shudders and almost feels like the transmission is slipping. Took the vehicle to a mechanic to diagnose the fault and they immediately knew what it was, engine transfer case failure. This is due to a design flaw allowing water into the transfer case that Porsche is aware of and yet to address. On some occasions Porsche will pay for the $5k repair but the part is still replaced with a transfer case with the same flaw. Transfer case failure can lead to a sudden lose of power and potentially cause death or serious injury if someone is traveling at highway speeds. Highly recommend addressing this with a recall for 2013 and 2014 Cayennes. I have experienced sudden lose of power due to transfer case failure, neatly resulting in a highway collision.