Rpm's rising in neutral!!!

I have a 2006 tiburon gt v6 5 speed and lately have had a problem, when im driving sometime when i put the car in nuetral the rpms will begin to rise or stay at the rpm level they were at when i put the car in nuetral. Also they will stay at a certain rpm even when i dont have my foot on the gas as if my car was on cruise control??? Please if anyone has any advice on what could be causing the problem and how to fix it, it would be greatly appreciated!

Clean your throttle body with throttle body cleaner. The butterfly/blade is sticking.
Franco