mine was doing this until recently.
as soon as i dropped it out of gear to approach any junction (roundabout, whatever) it would die. quite often would also stall when starting up to leave the house.
don't really know what fixed it but i did go on a very long journey up north with some prolonged high speed motorway driving, seems to have cleared its lungs!
either that or was a dodgy batch of petrol. i really don't know.
had been doing a fair few short-ish journeys which it doesnt really like. mate reckoned it was just coked up.