Mokka Knock Sensor Issue

It does sound like a potential knock sensor issue, given your symptoms. The increased fuel consumption and uneven idling are common indicators when the knock sensor isn't functioning correctly. Have you tried inspecting the wiring and plug connection to the knock sensor? A defective cable or a loose connection is a very frequent cause. Locate the knock sensor (usually on the engine block) and check if the connector is properly seated and if there's any visible damage to the wires. What's the mileage?

Thanks for the quick reply! I've had a look at the engine and I think I found the sensor. It's a bit awkward to get to, but the connector seems to be on okay. Is there any way to test the sensor or the wiring with just basic tools? I don’t really want to start poking around too much without knowing what I'm doing. Car has 108727 km on the clock.

Given your mileage and the symptoms, it's even more likely to be the knock sensor or its wiring. While you can try to check the voltage at the sensor connector with a multimeter, it's difficult to diagnose the issue accurately without proper diagnostic tools. You'll likely need an OBD2 scanner to read the fault codes and confirm the knock sensor is indeed the problem. If the connector looks okay, the sensor itself might be faulty. I recommend visiting a workshop. They’ll be able to properly diagnose it.

Thanks for the advice. I took it to a local garage, and they confirmed it was the knock sensor and, as you suspected, a faulty connector wire. They replaced the sensor and repaired the wire, the bill came to 95€. Runs like a dream now. Cheers!