V60 Cylinder Pressure Fluctuation

Cylinder pressure fluctuation with those symptoms on your Volvo V60 could stem from several things. Given it's a diesel, spark plugs are out. Have you noticed any unusual noises or vibrations from the engine? When was the last time the timing belt was checked or replaced, and is there any smoke coming from the exhaust?

I haven't observed any strange noises or vibrations. The timing belt was inspected approximately 20,000 km ago, and it appeared to be in acceptable condition. There is slightly more exhaust smoke than usual, especially during startup, though it dissipates quickly. Could you elaborate on the potential issues with the intake manifold or head gasket that might cause such a problem?

With the timing belt being relatively recent and no unusual noises, an intake manifold leak or a head gasket issue are less likely but still possible. Given the increased exhaust smoke and cylinder pressure concerns, it really points to something that's affecting combustion. If the smoke is black it is more likely an issue of unburnt fuel - which could be caused by a faulty injector. At this point, the best course of action would be a visit to a workshop, where they possess the equipment to accurately diagnose cylinder pressures and identify the root cause.

I took your advice and brought the car to a trusted workshop. It turned out to be a faulty sensor that was causing the fluctuations, triggering the check engine light and impacting fuel consumption. Fortunately, the repair was covered under warranty and the final cost was 0€.