Clean your isv. That should sort it. Just take it off (2 hoses and a plug) and spray the inside of it with carb cleaner spray. Some people like to soak it in petrol overnight but I always found the carb cleaner to do the job fine.
If you don't know where it is then looking at this picture of my engine you can see just above the rocker cover in front of the inlet manifold you can see a silver cylinder-shaped part, that's the lad you are after
Hope this helps, let us know how you get on.
If you don't know where it is then looking at this picture of my engine you can see just above the rocker cover in front of the inlet manifold you can see a silver cylinder-shaped part, that's the lad you are after


Hope this helps, let us know how you get on.