A flickering check engine light with rough idle usually points to an active misfire or fuel/air fault. Scan the codes, check ignition and intake first, and don’t ignore a flashing light.
Why a flickering check engine light and rough idle matter
On a Renault Kaptur, a check engine light that flickers while the idle feels rough is usually the car telling you that a misfire is happening right now, not just that a sensor has logged a fault. A steady light often means “store this code and investigate soon,” but a flashing or flickering light is more urgent because unburned fuel can overheat the catalytic converter. I’d treat it as a warning to diagnose promptly, especially if the idle shakes, the exhaust smells strongly, or you feel a stumble under acceleration.
