Matrix Ignition Problems

Sounds like a dodgy ignition switch alright. Rough running and cutting out points to an electrical problem, and it starting sometimes suggests a failing component rather than something completely dead. Have you checked the fuses? A blown fuse could cause some of those symptoms. The ignition switch sends power to a lot of the car's systems, so a problem there can manifest in different ways. Also, when you say 'rough running', do you mean misfires?

Yeah, I guess misfires would describe it. It kinda feels like it's chugging. As for fuses, I didn't check them specifically related to the ignition. Where would I find the fuse for the ignition switch? Is it marked clearly?

Fuse box is usually under the dash or in the engine bay. Your owner's manual should tell you exactly where it is and what the fuse is labeled. It might say "ignition", or "starter", or something similar. If it's blown, replace it with the same amperage. If it blows again right away, you've got a short somewhere and need a mechanic to trace it. Honestly, with those symptoms, and you're not super familiar with car electrics, taking it to a workshop would probably be best. It's hard to diagnose these things remotely.

Thanks for the advice. I found the fuse box diagram, and it turns out the ignition fuse was indeed blown. Replaced it, and the car started right up! The rough running seems to be gone too. Cost me 52€ at the workshop, but I'm back on the road. Appreciate the help!