Fiat Other Engine Revs Up

While The Car Is Neutral The Rpm Rises To 3000 And Never Goes Down. I Turned Off The Car And Turned It On, The Rpm Is 900, But When I...

Hi There, My Fiat Idea Petrol Seem's To Over Rev When I Change Gear For A Seond Or To Before Dieing Down Any Ideas. Can You Help Me!! I'...