After coming home from work this morning, I left my car outside (always garaged when home). After letting it sit outside for 5-6hours, I started it and let the idle settle at 600 rpm and the knock sound showed up. By the time i finished saying WTF the sound went away. The knock sound was there for maybe 3 seconds. After that she sounded perfect. I am starting to think, the sound is due to very cold weather. Today it was 70* so I am thinking in warm weather the knock sound will go away. This knock started when the temperature went below 40 degrees here.
Ghetto mods central!!