Vauxhall Astra, Vectra, Omega & Frontera 16V 1992 onwards
The most common failure for these vehicles is a breakdown of the cam sensor this will bring the engine management light on and can cause rough running and power loss. These sensor are easily replaced taking around 45 mins in total.
The next most common failure is the air mass meter usually costing around £250 depending on the exact model.
Vauxhall Astra, Vectra, corsa 1998 onwards
The single most common fault for these models is EGR solenoid failure normally the solenoid will need to be replaced but can also be cleaned out to prolong its life.
Vauxhall Corsa 1.4, 1.0 1997 onwards
Common fault with the idle stepper motor causing stalling and erratic idle speed, this is quite a simple fix with just three bolts holding it in place normally takes around 1 hr including reading and resetting the fault codes.
Crash-Data.co.uk reset and repair Vauxhall airbag modules after the airbags have been deployed or the seatbelts have gone off -
Crash-data.co.uk Vauxhall airbag repair list