Iv had my roush axle back exhaust for about a month. One thing I have realized with the axle back exhaust is the popping noise. IV had these on for about a month and it seems like it's getting worse. At first I thought the popping noise sounded sexy and beastly. But now its getting louder and it sounds like my car just exploded. Did anyone else experience this problem? And what exactly causes the popping noise?