revving

my mums 99 106 zest revs by its self especially after reversing. any ideas of what it is?

if its automatic,suspect air/vac leak.

my mums 99 106 zest revs by its self especially after reversing. any ideas of what it is? it has a manual gearbox.

I've had lots of engine management problems - nine in the first twelve mon ths including the revving.

could be some sensor, or steop engine. you might wanna let some one proffesional have a look.
those are known to be childhood problems of the 106.