So, I was driving home from school today, and I had my windows rolled down and no music playing and I heard a "knocking" noise from, what it sounds like, my drive shaft or transmission. It only knocks when I'm driving at a constant speed or with cruise control on. It sounds like something is knocking on the heat shield but I have no clue. It's weird because when i speed up, or slow down, the noise appears to go away. Please help...


04 GT rx8. 96k miles.