volkswagen sharan se tdi 1.9 ?

you will need to get diagnostic check to find out if fault codes stored the coil plug light will flash when driving if thee is a fault and what you are geting sounds to me like there is a faultwith the engine control unit or the power feed to it eg. relay also check your engine control unit for water ingress or corrosion at plugs on it it sits above the battery

danny
September 2010