Lumpy jerky driving

[Wilko1977]

Hi all, not sure how best to describe what is happening other than the title, when I am at low speed, the car is very very jerky, put accelerator flat down and car kicks down and drives fine(automatic), it is almost lurching along as you drive around a car park, no faults are showing up anywhere, any ideas what this could be?Also, can smell diesel once you have turned the engine off.

Thanks