Not that I know much, but I would start by taking Lambda sensor out and cleaning it with carb cleaner, my 206 would stall on tick over and hesitate when pulling away, cleaned Lambda and its fine now.
Then maybe change coil pack.
Had same problem on hot weather start . had to use the Gas for more than 5 minutes drive till it would work normaly
The problem was the step motor on the carb :thumb:. remove two hex screws and clean with WD40 . when testing outside its place ( Switch on , it should be pushed out ) , put it in side a box or some cotton as it may jump out .
It took me few hours to find the part inside the engine cavity