This happens randomly. I'll park the car one day, and it was fine all day, next day it will do it. It will also start or stop while driving. Basically the car acts like I keep touching the gas every second. At idle, it is two times higher than normal. You can hear the engine, sounds like I'm slightly revving every second. The time between revs is consistent as well.

 

Clean your intake air controller with some sea-foam. Let it dry and lube it with some silicone lube. Check your MAF sensor. Clean your temp sensor. Check your spark plug gap/signs of fowling and replace as needed. Change your PCV.