What RPM does your 4C cold start/fast idle at before dropping to idle? Mine seemed to be run faster/louder than it has been doing recently but I can't remember exactly what RPM it was before. Now it cold starts at about 1100rpm before dropping to about 800rpm idle. I'm pretty sure it cold started at 1300-1500rpm then dropped to 800rpm before. I don't know why... the weather has gotten colder so I would've expected the opposite.