I just changed my GT air filter elements today. After about 12k miles they were very dirty. My other vehicles usually go 20-30k very easily. If you have some miles on your GT you may want to take a look as it is easily overlooked. I suppose that with a supercharger and the way the very efficient air inlet system is designed these elements can get dirty in a hurry. The dusty farming enviroment in my area does not help things either.