@kwabi.motors: A bad spark plug in a Honda CR-V can cause several engine performance problems, including: * Engine misfires – the engine may stumble, shake, or hesitate during acceleration. * Rough idling – vibrations or an uneven engine sound when stopped. * Reduced power and acceleration – the vehicle may feel sluggish. * Poor fuel economy – the engine burns fuel less efficiently. * Difficulty starting – especially if one or more plugs are severely worn or fouled. * Check Engine Light – the car’s computer may detect misfires and turn on the warning light. * Increased emissions – unburned fuel from misfires can raise exhaust emissions. * Potential catalytic converter damage – prolonged misfires can overheat and damage the catalytic converter, which can be expensive to replace.