The morning temps in Nashville have been dipping into the 50's the past few days. I've been noticing a rattling noise from the engine around 2,500-3,000RPM when the engine is cold. Sounds like valvetrain noise (valves?) and is very noticable. Once the engine is warm, the noise goes away. Anybody else notice this? Is it normal for the K24? My Mazda 4 cylinder did this too, but was less noticeable. Even though I am a new manual driver, I don't think I over-revved the engine enough to cause any damage, and if I had, the noise would happen all the time. Any input is appreciated!