how can i fix my vectra 2.5 v6?

It is bound to be caused by a split or worn through vacumm or air pipe on the inlet side of the engine somewhere..? i would suggest either checking each pipe one by one or spraying a thin lube oil spray around each that way you will see it get sucked in by the engine and emmitted as a mild smoke from the exhaust for a few seconds or two..

steve
October 2006