S80 Poor Start Camshaft Sensor

That sounds familiar. I had similar issues with my old Opel Astra a few years back. Check engine light, stalling... turned out to be a faulty crankshaft sensor. Have you considered sensor testing?

Thanks for the tip. I suspected the camshaft sensor is defective. Is the crankshaft sensor problem the same as a camshaft sensor issue?

While not exactly the same, both sensors play a critical role in ignition timing and engine management. A defective encoder wheel on the camshafts is the likely cause. Given the symptoms, a workshop visit might be prudent.

You were right. Workshop confirmed camshaft sensor defective. Repair cost 695€. Thanks for pointing me in the right direction!