206 idle stop

My friends have my car 99 206 1.4 xr in my car, there is a problem like this, when I approach to the light, it stops when I get wasted to stop, but if I do not cut the gas, I do not have to worry, I need to keep it at constant speed. When I wasted, the same stops in the tube, I am waiting for your help.

It was stopping at me, there is a possibility of idling engine, I did nothing, it got better but I will see