My 2008 Aveo, which has just turned over 10,000 miles, has developed a loud popping sound coming from the rear of the car which lasts a minute or so when the car is started. Someone else mentioned this happening and it turned out to be some exhaust valve, but come on, this early in the car's life? Looks like I'll be using my warranty coverage again...
I've removed my back seat so it's even louder, almost sounds like the gas tank is farting. Also, the exhaust can make a quieter and slower popping/creaking as it warms up too.