P0441 purge sensor

Can anyone throw any light on my problem.

I have a 2007 1.8t A4 a few weeks ago the engine light came on for a few days then went off but there seemed to be no problems with it. All of a sudden 2 days ago it started running slightly lumpy and jerking when I accelerate whilst driving.
A friend plug it into his code machine and it threw up P0441.

Does anyone know what the issue is?

Thanks in advance

Have a read in this post stolen from elsewhere, different car but still in the Volkswagen Audi group so just the same VAGCOM 16825 P0441 fault code. Any quick fix? - Skoda Octavia I - BRISKODA.net

Make sure the fuel cap is on tight (clicks 6 times)