Diagnosing a P0300 on a Volvo XC60 T6

A P0300 ("random/multiple cylinder misfire detected") is one of the more frustrating codes to chase on the XC60 T6, because it rarely points at a single cause on its own.

This one started with a full OBD2 diagnostic pass and live data logging under load, rather than just clearing the code and hoping it stayed away. That live data is what showed the actual pattern instead of a guess.

The result: a confirmed cause, a fix that actually addressed it, and a clean scan on the follow-up drive — not just a cleared light.