speedo and rev counter?

I am after some advice

I have a 2001 clio 1.2 16v

Firstly i noticed a few days ago that my speedo is just given up, i can be doing 30 and it will jump to 50/60 then i can be driving along and its sat at 20, or at a stop it will tell me i am at 20mph, you get the picture!!

Then today i have noticed that the car is sitting at high revs, usually around 2000 this can even be at idle, my first usual thought with this is clutch but this was replaced about 2 months ago, my previous expriance with meganes tells me its ignition coils but its not juddering and well this is a clio

so both problems have me a tad confused, and im not sure if they are related!