During idle my car will bounce from 1000-1500rpm slowly for about 10 secs, then it will rev to 2000rpm and bounce faster. Its weird because the issue went away for about a day then came back. Any ideas?

 

Plans are the change out IACV and see if that helps. Any other input is appreciated.

 

Cleaned the iacv and problem went away. We'll see how long it lasts.

 

I'm having the same issue but at a lower rpm but what's the iacv??

 

Idle Air Control Valve.
Because our cars (Evo 8 and 9) are throttle cable and not electronic throttle, The ECU needs another way to regulate idle speed. Hence the valve. It is a pathway that bypasses the throttle body to regulate airflow when your foot's off the accelerator pedal. If it gets restricted with dirt, like your throttle body can do, it leads to symptoms at idle, specifically surging. The ECU is having trouble regulating the amount of air entering the intake through the IACV.
Try cleaning it AND your throttle body with a clean rag and some carb/choke cleaner. Even though your throttle is closed, there is supposed to be some air getting past it, so some build up there can cause an exaggeration of the idle air control issue.
Hope that helps.
Whoops, I see you have an '09. I'm not sure if Evo 10's have electronic throttle (I'm guessing they do) but all you have is the throttle body. Just clean it, then.

 

Issue is back. New iacv on the way and sending off throttle body to mil spec for the works.

 

Yea I figured that's what you were referring to and yea good idea about the throttle body forgot about that. I ordered spark plugs and an air filter even though it wasn't too dirty. I'm hoping doing that and disconnectin the battery will solve my issue but if not I'll just bring it into the dealership because I still have a warranty. It is throwing a code but it's something wierd like C something?!? I think my Evo scan is throwing a faulty code