C30 Cold Start Rough Idle

Sounds familiar! I've got a C30 too, and I had similar issues. Have you had the injectors tested? Could be worth checking the fuel rail as well. Maybe try some injector cleaner first?

Thanks for the tip! How did you eventually fix your C30? Did you end up replacing the injectors, or did cleaning them do the trick? Just trying to get an idea of what I'm in for!

Cleaning didn't do the trick in my case, unfortunately. I had to get the faulty injector replaced. Honestly, I'd get yours checked out by a workshop if the cleaner doesn't help. It's a pain, but better to be safe than sorry!

Thanks a bunch for the advice! I took it to a workshop, and you were spot on – it was a defective injector! Cost me 515€ to get it sorted, but the car runs like a dream now. Really appreciate the help!