Were you ever able to remedy this issue? Recently purchased a 2015 Yukon and I’m having a strong exhaust smell at idle. When driving and then parking it doesn’t smell bad til it sits idle for a few minutes. I can drive and park get close to the tail pipe and no smell for about 1-2 minutes then it gets really strong, drive some more it goes away til 1-2 minutes of idling and it’s back. It happens at start up or after driving and a few minutes of idling. Any advice would be greatly appreciated.