mk2 Ocy scout 2ltr TDi

Hi All, My 2009 mk2 Octavia Scout TDi (BMM) has a lumpy tickover so what channels in VCDS do I monitor ? and is it better to monitor one line of 4 sensors to then display on the scope or can you monitor say 30 channels and then pick out some to display to narrow the fault down, are there any common sensors that would cause the fault ? cheers Stuart