In order to find the remedy, you first need to know the cause. On this vehicle, the P0300 code indicates a misfire in one or more of the cylinders of the engine. In the majority of cases, this can be traced to a faulty coil, high-tension lead, spark plug, computer or even the fuel system. The warning shows that one of the cylinders is not firing as cleanly as it should be, so those are the basic thigs to start with. The problem could be as simple as moisture inside one of the coils or its fittings, or even a simple dodgy spark plug. If that’s the case, replace all of them, rather than just the one that’s faulty, as the rest are also likely to be getting towards the end of their life.

Parts and service supply has been a bit of an ongoing problem for some owners of these earlier Chinese-made Great Wall commercial vehicles. Some were sidelined for extended periods after some service parts were hard to locate and it’s doubtful that Covid and its attendant supply-chain problems have helped in that regard.

I’m a bit surprised, however, to learn that a Great Wall dealership lacks the tools and techniques necessary to carry out just about any maintenance task, including electrical jobs. Perhaps a call to Great Wall’s Australian customer service number might do the trick. If your nearest dealers don’t have the necessary equipment, perhaps there’s another dealer a little farther away that does. Failing that, try one of the many online forums for a solution. Chances are your vehicle won’t be the only one with this specific problem, and other owners may be able to offer advice on who can carry out the work.

These cars have a pretty terrible reputation of reliability over the longer term. Plenty of things seem to go wrong with them (almost certainly thanks to them being built down to a price) and parts supply seems a bit sketchy at times, too.

A loose gearshift mechanism can certainly cause the problems you’re experiencing and a loose, or sloppy gear-stick can be the first symptom. Often it’s a simple case of adjusting the selector mechanism, other times you may need to replace a worn bush or bearing to restore the shifter to its original state. But if the shifter is worn or damaged, then selecting gears can become the problem you’re experiencing.