Ok, I have a 03' Cobra with a whipple S/C. If I take the car out of the garage cold I "sometimes" have a rattling sound coming from the engine bay when accelerating between 1st, 2nd, and 3rd gear at about 2500-3000rpm. After about 1-2 miles when the engine gets a little warmer it stops. No power loss and it isn't every time I drive it. It doesn't sound like the notorious ticking sound from what I've read and I don't really know if detonation would be so inconsistent. It almost sounds like valve rattle but this is my first corbra and I really don't know all the little quirks that come with owning them yet. So if anyone has any ideas I would appreciate it. And how to fix it....LOL.