Vectra 1.8 Cold start

[Bill]

Can anyone tell me what adjustment I would have to make to remove the hesitation when starting from cold. It idles fine but in trying to pick up speed there is hesitation in every gear until the engine has warmed up. Is there an auto choke somewhere needing lubrication or do I have to take it to a shop for an expensive visit for a problem which might be a simple adjustment. Your help is appreciated

 

[me140]

No choke - all electronic and self regulating. Is it misfiring? Could be plugs, leads or coil pack if so.