SR20 rattling and idle trouble!

[8chino8]

so i have this rattling coming from the motor that sounds like a clinking noise. it only comes when i first start the car cold then it goes away.

I also have this problem when im in neutral and i rev it up and let go of the gas the idle drops down to like 400 rpms then floats up to 1300 rpms then floats between 1000 rpms and 1400 rpms. then it just stays put at 1400rpms.

I also have this problem when i gun it, the car picks up then seems to miss fire a few times while picking up speed. then after driving for a while it doesnt do it anymore.

somone please give me some words of wisdom!