Posted on 11/28/2025
A car should settle into a calm, even idle after it warms up. If the steering wheel trembles, the seats buzz, or the hood dances a little while you sit at a light, something is off. Rough idle can feel worse with the A/C on or when you shift into gear. The good news is that a handful of common issues cause most idle shakes, and a careful inspection can narrow them quickly. What a Healthy Idle Feels Like On a healthy engine, the tachometer stays steady and the exhaust note is smooth. You might feel a faint hum from the road, but not a cyclical shake through the wheel or pedals. The idle should remain stable when the engine is fully warm, the cooling fan cycles on, and the alternator or A/C clutch adds load. If rpm dips, surges, or the whole car shivers, the engine is either struggling to breathe, to meter fuel, or to handle added load at low speed. Misfires ... read more