I OWN a VS II Holden Calais that runs like a charm, though there seems to be a problem with the fuel consumption. By my calculations it gets 15.6 litres/100km and I'm lucky to get 300km from a full tank. It's been the same since new. I have had it checked, but I've never had an answer that would explain the problem. Is the economy within the bounds of expectations with this car?
If your calculations are correct, your car isn't returning the fuel consumption it should. The Australian Design Rules (ADR) test fuel consumption on your car is 11.5 litres/100km city driving and 7.2 litres/100km highway driving. From those figures I'd reckon on getting 11-13 litres/100km in normal round-town driving conditions. I suggest you take it to a Holden dealer to have it checked again.
Disclaimer: You acknowledge and agree that all answers are provided as a general guide only and should
not be relied upon as bespoke advice. Carsguide is not liable for the accuracy of any information
provided in the answers.