1.2TDICR jumping on idle

Hi, 

my 1.2TDI CR Greenline 2 estate has an intermittent idle issue. 

It sounds as though it’s jumping, as the engine sound changes, sort of like a cold lawnmower, although the rpm gauge doesn’t move at all. It doesn’t sound like it’s going to stall, and it doesn’t seem to depend on the weather or anything. It’s not had the emissions change.

It did have a leaky egr cooler a while ago, but I believe that’s been sorted because nothing came up on the last mot. 

It has been doing this intermittently for a while now, and there doesn't seem to be a pattern to this, although sometimes when stopping the engine note changes after a second of idling. 

Thanks

Edited 1 December, 20196 yr by CS45