Holden Sedan Range

Perhaps you’re looking in the wrong place for the answer. The ignition system is only part of the driveline that makes the whole thing work. A problem like this one could easily be caused by a problem in the fuel system.

In fact, the fact that the problem only happens in cold weather would make a lot of mechanics check the fuel system before fiddling with the ignition. That’s because, when an engine is cold, the fuel and air mixture needs more fuel and less air to get the thing started initially. If there’s a problem in the fuel system such as a clogged or dirty filter, an air leak or a slack fuel pump, you could potentially see the exact symptoms you have.

The problem could also lie in the injectors or any of the electronics that are supposed to tell the engine’s computer that it’s cold outside and a richer fuel:air mixture is required.

Have the car checked out by a mechanic who will be able to check all these parts for correct operation and then start replacing bits and pieces; not the other way around.

Modern automatic transmissions are pretty complex things and there’s a lot that can go wrong from the simple low fluid level to the catastrophic like a broken torque converter or failed valve body, gearset, oil pump or clutch pack.

But mechanics know that the first sign of this transmission failing totally is a refusal to select Drive. Take the car to a transmission specialist who will have seen these symptoms before and will have a pretty good idea of what’s going on before they even lay a spanner on the car. And be prepared to replace the transmission as the only proper fix.

A second-hand transmission from a wrecked Commodore might be an option, but only if you can prove that the unit has done moderate mileage and, therefore, is probably not about to produce the same symptoms as yours already has.

Presumably the car makes this noise when you hit a bump or undulation. The Commodore’s front end is not particularly complex and is, in fact, a pretty standard MacPherson strut set-up.

With that in mind, there are only so many things that could cause the front end to bang or rattle, including a worn ball-joint, tie-rod end, or suspension bush. But don’t forget about the bushes in the steering rack, too, as these can contribute to a noise from the front end.

If all the suspension checks out, then you need to go a bit deeper into things like the cross-member mounts, engine mounts and even wheel bearings. Any wear or play in these components will cause a clunk in the right circumstance.

If none of that helps then you need to look beyond the suspension and into areas like a loose battery tray in the engine bay or even a loose piece of trim or sheet metal somewhere on the car. Exhaust heat shields are prime candidates for this, as are the metal shields at the back of each brake disc.