Greetings everyone, may someone provide assistance to me? I own a 64 plate cdti insignia with a 163bhp engine. Generally, it has been functioning well, except for the current issue of an irritating vibration when driving. It seems to be a case of a loose exhaust or a loose heat shield, among other possibilities.I have rebuilt a gearbox mount that had a torn rubber bushing, but the vehicle remains same and it is frustrating. What is the cause of this vibration? Could someone provide guidance or recommendations?