Koleos rough idle high fuel consumption

Greetings. Given the symptoms described – the malfunction indicator lamp illumination, elevated fuel consumption, and uneven idling – a defective knock sensor indeed seems probable. It is imperative to ascertain the integrity of the sensor's cable and plug connection. A degraded or compromised connection can often mimic the behavior of a failed sensor. Employing a multimeter to assess the continuity and voltage at the connector would be prudent. Have you had the opportunity to conduct such diagnostics?

A multimeter, huh? I'm not super familiar with using one, to be honest. Where exactly should I be testing on the sensor and what readings am I looking for? Is this something I can realistically do myself or am I getting in over my head?

Considering your admitted unfamiliarity with multimeter usage, I must cautiously advise against self-diagnosis in this instance. Erroneous measurements or improper handling of electrical components can potentially exacerbate the existing issue or even induce further complications. Given the described circumstances, proceeding to a qualified automotive workshop for a comprehensive diagnostic assessment would be a judicious course of action. They possess the requisite tools and expertise to accurately pinpoint the root cause of the malfunction. Replacing a defective knock sensor, including labor, should cost about 95€.

Okay, makes sense. Appreciate the advice! You're right, I think I'll take it to a workshop. Sounds like it's probably a cable issue like you said. They replaced the knock sensor, including labor, for 95€. Thanks again!