106 - Engine problems

My 106 1998 zest is at times struggling to start.

When it does start it will run ok until i approach traffic lights and
roundabouts when it sound and feels as if it wants to cut out.

Any ideas about posssible causes are very welcome...

 

I've had 2 106's in the past year and mine both cut out when stood at
lights. They also do the opposite where they rev up high without touching
the pedals. Peugeot dealer just looks at me like im insane!