Volvo V50 Misfire

I had similar symptoms on my old Opel Astra, though it was a diesel. It turned out to be a faulty fuel pump. Have you checked the fuel pressure? A weak fuel pump can cause misfires, especially under load because the engine isn't getting enough fuel to maintain proper combustion. A fuel pump ensures there is adequate pressure of fuel to supply the engine, so the injectors can function properly.

That's a good point. I hadn't really considered the fuel pump. How did you diagnose the fuel pump as the problem in your Astra? Did you just measure fuel pressure, or did you do more?

I simply measured the fuel pressure, and it was significantly below the specified value. At that point, further investigation was unnecessary. I would suggest taking it to a workshop to diagnose. They'll be able to confirm if it's the fuel pump or injectors.

Thanks for the advice. It was indeed a defective fuel injector, specifically on cylinder number four. I replaced it, and the car is now running great. The total cost was 515€, which I think is reasonable.