I have a 2.0 cdti insignia 2011with 64500 miles on it and have recently came across a slight judder when the engine is cold. it has just recently had a service and mot check and everything was good but this has happened a week after the service and mot. I have checked and the spark plugs weren't changed during the service. I am abit worried regarding the problem and hope it is something small and cheap to fix. could someone give me some advice or info on what it could be