Mazda Skyactiv-X

Mazda's compression-ignition petrol — the 2.0 in the 3 and CX-30, and the 3.0 straight-six in the CX-60.

⚑ It burns petrol the way a diesel burns diesel, and that is not marketing. Under most of its operating range the mixture ignites from compression alone; the spark plug fires to create a small expanding flame kernel that raises the pressure enough to set off the rest. Mazda calls it spark-controlled compression ignition, and the catalogue's own note on it is the right summary: it behaves like neither.

So both bodies of experience mislead here. A petrol technician's instinct about knock is wrong, because controlled knock is the combustion mode. A diesel technician's instinct about injection timing is wrong, because the fuel is petrol and the transition between modes is what the control strategy is really doing.

It carries a supercharger that is not there for power. It supplies the very lean mixture the process needs, which means a boost-related fault presents as rough running rather than as a lack of performance — the opposite of every other supercharged engine.

It is direct-injection and it is mild-hybrid, so intake-valve carbon and belt-starter-generator faults are both in scope. A start-stop or charging complaint on one of these is a question about the hybrid system, not about the engine.

Specialist experience is genuinely thin and generic advice is actively risky here. Where a procedure exists, follow Mazda's.