can anyone tell me what are the signs that the crank shaft sensor has gone or is going on the vauxhall vivaro? when i start it in the morning i have no revs for about 5 minutes then it just shoots up i am then able to drive as normal it also blows white smoke.it has recentley got worse & now when i pull off i have no power.i have changed the cam shaft sensor,the egr valve,the air filter,the diesel filter & the mass air flow sensor.my engine managment light is not on.after having trying almost everything someone has now suggested it could be the crank shaft.any info really appreciated as i am now at a loss ,thanks michelle