High fuel consumption was a major criticism of these cars when they were brand-new. The combination of a heavy car and a large capacity engine meant that the Crewman was never a fuel sipper. To be honest, the absolute best way to reduce its fuel consumption is in the way you drive it. A light foot on the accelerator might just have a bigger effect than you imagine when it comes to squeezing every kilometre out of every litre.

But there are other things to do as well. Start with the tyres. A tyre that is under-inflated can cause a vehicle to use more fuel, but frequent tyre-inflation pressure checks can help. Of course, the car’s safety is dependent on correct tyre pressures, too, so it’s not just fuel economy at stake here. Either way, start at about 30 or 32psi (more if you’re towing or carrying heavy loads) and don’t let the pressures drop below that level. Correct wheel alignment can also influence fuel economy and don’t forget to keep the engine tuned and running sweetly as a well-tuned engine will always use less fuel than one that is out of adjustment. Ute owners often fall into the trap of carting around a lot more gear than they need (because they can). Removing weight from the vehicle’s tray will also help cut fuel bills.

If it has come on and stayed on it means you should get it checked, it could be a number of things that caused it, and you need to have it checked by a mechanic to determine the exact cause. If there isn't any obvious change in the way the car drives there's probably not much to be concerned about, but it the car isn't running the way it was, and the light is still on get it checked.

Ignition coil failures have been an often reported failure on Commodores going back a number of models; it's not necessarily something new. I couldn't say the others will fail any time soon, after all the two failed coils did 184,000 km before giving up.