My car shouldn't idle at 3000rpm should it?!

Since Sunday shes not been idling quite right all the time - any ideas what it could be?! Sometimes shes fine, sometimes its sky high! Stopped at some lights on the way home and she sat at a constant 3000rpm until I moved off again!

is the injector light on?

Far as I know the only lights on were the headlight icon and the key code one!

STICKY THROTTLE CABLE? ECU?

Sounds like the idle stepper motor in the idle control valve. Take a look at your throttle body and use some brake cleaner or carb cleaner with a toothbrush and give it a clean up. Also check the wiring connectors coming form the motor.