Volvo S60 engine power loss

I had similar symptoms on my S60. A faulty MAP sensor can definitely cause those issues. Have you checked for any obvious vacuum leaks? That's often the culprit.

Is it possible that even a small, undetectable leak can lead to such significant performance issues? I haven't been able to identify any.

Yes, absolutely. Even a small vacuum leak can throw off the manifold pressure readings, leading to the problems you're experiencing. Considering the symptoms and your inability to find a leak, it might be time to consult a workshop. They can perform a smoke test to pinpoint any leaks and properly diagnose the MAP sensor.

A local workshop visit confirmed a significant vacuum leakage, leading to the faulty manifold pressure sensor. The repair, including parts and labor, cost 235€. Thanks for pointing me in the right direction.