My rev counter is crazy!

When at lights/stopped, ie handbrake on, in neutral, both feet on the floor.
The rev counter bounces between 1000/2000 rpm?
Does anyone know why this could be. It only does it every now and again but it has done it a few times.
I have also noticed its not always at the same times, i could be driving for a while or only started the car and it will still do it.

hi maxine . start with basics . clean out the throttle body using some spray carb cleaner . sounds like the butterfly is stickin or not closing properly possibly telling your icv to give more fuel /air . try this first as it costs pennies to do yourself .if this doesn t work let me know .

Obv that meant nothing to me lol
But i said to Mark last night and he said at the weekend, he will have a wee look.
I will let you know how we get on

thanks
maxine

no problem . if your havin problems give me a call and i ll run through it with you or mark .if you get nowhere you can run the car out to my house and i ll have a look at it for ye !don t worry ive got the experience and the equipment !lol