ghost.223

I tried the seafoam spray and it seemed to work fine

C5Natie

I dont think we should forget the possibility of some type of engine damage causing the detonation. My car, and actually every C5 Ive ever heard myself, didnt make that much noise on a cold startup. OP, I guess you can try to clean up any carbon, and I would suggest maybe even removing the tb to check for oil in the intake, but if the noise persist afterwards you should really look into it. Maybe hook up a wideband and check the afr under load.

Oldvetter

Using a Top Tier Gas can help carbon build up:

http://www.toptiergas.com/

I also use Techron Plus every oil change.