Whenever my car is first warming up the rpms go up to about 1 - 1 1/2 and drop and then climb back up again...so on so on, Until a couple minutes when it's warm up it stops doing that. Seems like a minor problem, but does anyone have any thoughts on what it could be? It's a d16z6 bone stock except for a short ram intake.

 

Your fast idle thermo valve is probably clogged.