Started my GTS after it sat for over a week in the garage. Holy Guacamole did it sound like crap. Tappet noise was so loud it sounded broke. After letting it warm up for awhile and shutting it off and restarting a few times it got progressively quieter. Finally after the oil got up to 190 degrees it sounded normal again. I'm glad no one was around, I would've been embarrassed.
Anyone else ever experience this?