I have a manual daihatsu feroza. Generally while the car is in neutral or im waiting at the lights the car would be idling high. Why is this?

I have a manual daihatsu feroza. Generally while the car is in neutral or im waiting at the lights the car would be idling high. Why is this?
Hi from Greece,if idling revs up only while you depress the brake pedal ,there might be a vacuum leak at the servo unit.If high reving happens irrespectable of braking,then the fault might be a tight accelerator cable,a vacuum leaking from a hose or elsewhere at the intake manifold area or an electronic fault from a sensor or throtle valve position potensiometer.Althougt my answer isnt "feroza" specific,hope it helps.Regards.