Which of the following is a sign of a malfunctioning suspension system?

A leaking air suspension is a clear sign of a malfunctioning suspension system. The suspension system plays a critical role in maintaining the vehicle's stability, handling, and comfort by supporting the weight of the vehicle and absorbing road shocks. When an air suspension leaks, it fails to maintain the required air pressure, which can lead to an unstable ride, improper vehicle height, and potential difficulties in handling and braking. This issue can result in uneven tire wear and may compromise safety, making it crucial to address any leaking components promptly.

In contrast, stability during driving, normal handling, and no unusual noises indicate that the suspension system is functioning properly, as these signs suggest that the vehicle is maintaining its designed level of performance and comfort. Therefore, noticing a leak in the air suspension is a significant warning of impending issues that could affect the vehicle's overall safety and driving dynamics.