I'm bumping this because I've been getting it randomly also. I used a stethoscope on every single pulley and there was nothing out of the ordinary. I'm going to check the starter in the next couple of days.

 

Here in the last month, my car has a rattle on startup and sometimes at low rpms driving around too

 

Careful, shortly after it blows up when you vtec....

the rattle is just the car, most of them make them. You can even catch it in the top gear review many moons ago.

 

i have some rattling, drives me insane, idk wtf it is, but it makes me pretty mad sometimes, specialy in my parking garage, everyone seems to hear it lol, maybe im paranoid, but its bad, and a valve adjust didnt fix mine