It honestly doesn’t sound too bad given the average dealership labour rate is usually something like $160 or even $200 per hour to the customer. Also, genuine Holden parts for this type of job will always be preferable to aftermarket parts, and if the quote is to drive the car in and drive it out again with a brand new turbocharger working perfectly, then the price is probably pretty good.

If you want to save money, you can always try to find an independent workshop, but make sure you use one that knows this type of car and this type of repair. And don’t be afraid to ask about where the new parts are coming from.

This could simply be a case of the engine’s idle speed being set too low. If that’s the case, even though it’s firing on all four cylinders, it can feel rough and lumpy as though there’s something major wrong. Then, as you increase the revs, the engine smooths out and feels normal again. Even a worn or broken engine mount can amplify vibrations at idle, as can an exhaust leak.

A good mechanic will be able to tell you quickly whether this is the case or if, in fact, the engine really is dropping a cylinder at idle. If the latter is the case, you may have a dud spark plug, ignition wire, sensor or even a blocked or dirty fuel filter. Again, most mechanics won’t have a problem tracking this one down.

The fact that the scan doesn’t throw up a fault code could be an indication that it’s something pretty fundamental at fault here. Have you checked the car’s earth points and the tightness and cleanliness of the battery terminals? Apparently simple things like this can easily cause a random misfire. How is the condition of the battery and the charging rate? Modern engines hate low operating voltages.

But don’t rule out a problem with the fuel system, either. You might have a faulty fuel pump or a dirty fuel filter or even a dud injector that’s causing the glitch. Don’t forget to check the wiring to these components, either as a simple loose wire could be the problem.

If you do need to dig deeper, you could try checking the engine’s compression and the clearances of the engine valves. Even something like a cracked cylinder head or faulty head gasket can cause a misfire that shows up at, say, a particular engine temperature, but not at other times.