Welcome to the forum, could be a number of things, possibly TDC sensor or a split in a vacum pipe to the MAP sensor. Click the link in my pic for the Clio FAQ, there are a couple of threads covering similar issues under "engines" which may be of help.
Just thought I would update this old thread in case it benifits other members.....sorry I don't be online very often (yeah right!)..... the problem was the coil pack.
It was changed and no sign of the spluttering since.