Laguna cold start misfire

Sounds like a plausible diagnosis. A defective injector could definitely cause those symptoms. Does the misfire clear up once the engine warms up? Have you tried any basic troubleshooting steps, like checking the fuel pressure or pulling the injector connectors to see if one makes no difference to the rough running?

Thank you for your insights. Indeed, the misfire diminishes as the engine warms. Regarding your suggestions, could you elaborate on the process of 'pulling the injector connectors' and what outcome I should anticipate? I'm moderately adept technically, but precise instructions would be greatly appreciated.

Okay, so the misfire improving with temperature definitely points towards an injector issue. When I say 'pulling the injector connectors,' I mean disconnecting each injector, one at a time, while the engine is running (albeit poorly). If you disconnect a faulty injector, the engine's running quality won't change, because that cylinder wasn't contributing anyway. However, disconnecting a working injector should make the engine run even worse. If pulling a particular connector doesn't change anything, that's your prime suspect. But honestly, at this point, I'd advise taking it to a workshop for a proper injector test. Could save you a lot of hassle.

I appreciate your detailed explanation and candid advice. Taking your suggestion, I entrusted the Laguna to a reputable workshop. Their diagnosis corroborated our suspicions: a defective injector. The repair, including parts and labor, amounted to approximately 515€. The Laguna now starts flawlessly. Thank you again for steering me in the right direction!