Posted on 6/26/2026
A rough idle can make a car feel unsettled even when it is still driving. You stop at a light, and the engine shakes a little. The RPM needle moves around. The steering wheel or seat vibrates more than it used to. Then the car seems better once you start moving again. That kind of symptom is easy to downplay, but it usually means the engine is not firing as cleanly as it should. A rough idle can come from several places, and an engine misfire is one of the big ones. A proper car tune-up can help when worn service parts are part of the problem, but the cause still needs to be confirmed. What A Rough Idle Is Telling You An engine should idle at a steady speed with each cylinder contributing evenly. When one cylinder is weak, late, rich, lean, or not firing correctly, the engine loses that balanced feel. That is when you start feeling shaking, stumbling, or uneven RPM at a stop. A rough idle can be mild at first. Some drivers notice it only after startup, with the A/C ... read more