Had a '06 VZ Calais since 2008. Problems I have had (nothing major BTW)
- Rear parking sensors were working intermittently when I bought it. Fixed by replacing wiring harness under warranty back in 2008. Not a problem since.
- O2 sensor giving check powertrain warning. Fixed under warrany by replacing faulty sensor back in 2009. Not a problem since. Common issue and nothing to worry about.
- Oil pressure sensor giving check powertrain warning. Fixed by by replacing faulty sensor this month. Common issue and nothing to worry about.
- Ignition barrel hard to turn on hot weather. Fixed by injecting a small amount of graphite powder into the barrel. Been a problem since the VT apparently.
Really, none of the above were any great inconvenience or drama. I bought it with 77,000km and it now has around 180,000km and it still doesn't have a rattle. The VZ had most problems ironed out from earlier models and are probably one of if not the best commodores ever made. I drive it 60km to work and back every day. It has been from Canberra down to Tassie, all the way around the island and back (4000km) without a problem. I recently did a similar trip from Canberra to up past Bundaberg in Queensland and back (another 4000km trip) again with no problems. Great car.