Which of the following symptoms may indicate a problem with a vehicle's suspension system?

Excessive vibrations during acceleration is a clear indication that there may be an issue with the vehicle's suspension system. The suspension is responsible for maintaining proper contact between the tires and the road, absorbing shocks from bumps while providing stability and comfort. When there is a problem, such as worn or damaged components, it can lead to improper alignment and handling characteristics, which often manifests as vibrations, especially during acceleration. This symptom suggests that the suspension is not functioning effectively and may require inspection or maintenance.

In contrast, increased fuel efficiency, improved steering response, and quiet operation typically indicate that the vehicle's systems are functioning well rather than signaling any malfunctions. Increased fuel efficiency and improved steering response suggest that the components are doing their job efficiently, while quiet operation generally means that there are no abnormal noises suggesting failure or friction in the system.