I'm getting a horrible sound around 45 mph in 4th gear at around 2300-2500 rpms while flooring it. Sometimes in other gears too while flooring it but it's somewhat unpredictable. Would it be a heatshield? If i bang around i dont hear anything other than in the cat i can hear a tiny little rattle if i hit it real hard w/a hammer. But i dont see how that could make all this rattle. It more so sounds like it's coming from rear u-joint/3rd member area but hard to say since i'm driving while it's going on. Anyways can you solve the mystery thanks guys.