2002 Accent idle throttle problems help plz!!!

Hi, my accent is idleing at its own desire. I have to have my brakes on very hard then i'm at lights cuz it will get up to even 2-3k rpm without me even touching the throttle. On freeways with a steady speed it will shoot up the rpms for no reason in little spurts. I took it to the dealership and they said to change the spark plugs and new wires and it should run fine but it is still having the problem someone help please!!??!!