2015 Holden Colorado Pricing and Specs

The starter motor would be a very good place to start looking for the problem. If the battery checks out (and that presumes you’ve load tested it, not just run a voltmeter across its terminals) and the addition of a second jump battery only just turned the engine over, then, the starter motor is a likely suspect.

But don’t forget things like a poor earth somewhere on the car or a dodgy ignition or starter button. Once the engine is running, check the power going into the battery. You should be looking at between 13.2 and 14.5 volts going into the battery with the engine running if the alternator is pulling its weight.

Just because the battery indicator is showing green, does not mean categorically that it’s in good health. It can produce a surface charge that might show 12 volts with no load on it, but can fall to its knees when you load it up with the starter motor.

A diesel that will turn over but not fire will often have a problem with its fuel system as the cause. You may need to check the fuel pressure and the pump itself, but other causes can be blocked or worn injectors and blocked or dirty fuel filters. A car with faulty glow-plugs can also be difficult to start from cold. But even things like a blocked air filter or something else fundamental to the car's operation could be the cause. And while it sounds simple, is there actually fuel in the tank?

If the solution doesn't present itself simply, the best advice is to have the car electronically scanned to check for fault codes the on-board computer will have logged.

A wobble or vibration big enough to be felt through the floor that suddenly occurs for no reason, can often be traced back to a wheel balance issue. If the wobble is worst through the car's steering wheel, it's likely to be a front-wheel balance issue, otherwise we'd be looking at the rear wheels.

The generally terrible state of our roads at the moment is probable cause for this, and a decent impact with a pothole can be enough to dislodge the small weights on a car's wheel that make it balanced and, therefore, rotate smoothly. When you consider how fast a wheel is turning at 100km/h, you can imagine that a small imbalance can be enough to produce a big wobble.

The good news is that this is a simple fix. A visit to a tyre specialist will soon determine of a wheel balance problem is the issue and it can be fixed quickly and cheaply with the replacement of the small, lead weights which are stuck to the car's rim. While the wheels are being checked, it's a good idea to examine the tyres, too. A tyre with structural damage or a flat spot an also lead to this type of problem.

If this doesn't turn out to be the cause of the wobble, you then need to move on to other components like the driveshaft and universal joints and even suspension bushes and shock absorbers.