SNAP, I've had the same problem for around two years now. Not really impressed with Vauxhall (UK) as I live in Germany. Opel on the other hand have no real record of the problem.
The problem may be a loss of pulsed earth from the ECU to the Ignition pack. This causes the juddering that you experience (one cylinder will not be working/sparking properly). Not only ESP (electronic skid protection) lamp but Engine Management lamp lit.
This can be really expensive to diagnose as I have found. When the vehicle is diagnosed numerous garages have replaced various components mass air flow sensor/chamber compression checked etc(very costly) with no overall solution to the problem.
Today (29-10-09) I have paid 780 Euros to replace the ECU. The car was running fine this afternoon but after a short trip moments ago the car has returned to square one..........AAAAAAAAAAAAAAAAhhhhhhhh
I am very tempted at present to return the vehicle to the Vauxhall dealership that sold me the vehicle as they washed their hands of the problem as soon as they could. Great aftersales care I must say......... Well done Hartwells, Southampton.
Very tempted at the moment to search for a new Ford.
Jase (Germany), October 2009