Running rough between 1,000 & 200rpm
 

Hi there,
I have this little niggle with my 2.7 986 - between 1,000 and 2,000 rpm it runs really lumpy; stutters and splutters a bit and power is reduced. As soon as it passes 2,000 it absolutely sings!
I've tried cleaning the MAF sensor and also changing the MAF, hoping this was the issue, but unfortunately to no avail. It doesn't smoke, tick over is more or less stable
Any suggestions would be very welcome.