Berlingo cold start rough idle

Cold start problems can be tricky. Fuel injection is a good place to start. A cold engine needs a richer fuel mixture to start properly. Are you seeing engine misfires or rough idling, especially when the engine is cold? An injector might be clogged or faulty.

Yes, I observe rough idling when the engine is cold. What's a 'richer fuel mixture'? If the injector is the cause, can it be cleaned, or does it need replacement?

A richer fuel mixture means more fuel compared to air in the air/fuel mix. Cleaning it could help, but if it's defective, replacement is usually the only real fix. Given the symptoms, your injection valve is a likely culprit. I'd recommend a professional diagnosis at a workshop to be safe.

I took it to a workshop, and they confirmed a defective injector. The repair cost around 515€. It runs smoothly now, even on cold starts.