dodgy speedo

[L maf]

right ive got a phase 1 clio sport and when i put my foot down my speedo has a mind of its own itgoes all the way round 2 160 and jumps all over the place

what could cause this
thanks

 

[edde]

most likly the speedo sensor in the gearbox needs chnaging easy enough to do cannot miss it realy its the only sensor on your box