I had a 205, same engine. drain the water from the fuel system ( there was a tap thing under the filter) change the fuel filer. My one had done a 150,000 miles and never had the injectors cleaned, but the haynes maual will say the stalling a idle speed is faulty injectors. Big suggestion to drastically help is : REDEX. buy a bottle of it( the one for diesel engines ) and tip the whole lot into one tank of fuel ( small bottle that should treat 4 tank fulls ). this stuff works wonders, will clean the fuel system and injectors. for the sake of a fiver, well worth a go
good luck
alf.,