FTO AUSTRALIA

Hi guys

I was wondering if anyone can put me in the right direction
my speed metre has goon retarted
when i accelerate all of a sudden the km needle jumps to 100km/hr
and sort of keeps jumping then it will go back to normal
i have just bought new Kumho tyres i thought it might fix it for more grip
but still disame
any clue guys?

Could be speed sensor stuffed but tires would have no effect hope you bought 712's ku31 or ku21's no point with any of others