It was driving down the motorway at 75mph and lost all power. The engine cut out, it was knocked out of gear to coast to hard shoulder. Car would not start again. RAC came out, put car on fault reader, fault codes were; P1525 P1550 P1526 and P0325. All these faults were reset, car started but was advised not to drive it home due to tapping noise coming from what sounds to be the tappets. car was recoverd home. RAC report says cam shaft knocking, suspect low oil pressure from pump. The car is a z18xe engine, could anyone help on where to start looking?