Compared to the smooth rides most drivers are used to, having a vehicle suddenly begin shaking can be quite worrisome. Car shaking is not an entirely uncommon problem, but it is something that likely indicates a problem with your vehicle. Unfortunately for drivers, this symptom can have a variety of different causes, so it's important for owners do a bit of troubleshooting to determine exactly what the problem is.
First, owners need to narrow down the problem by figuring out what conditions are causing the car to shake. Many drivers, for example, will say their car is shaking when it's really the steering wheel that is actually vibrating. Other times, the entire car may be shaking or slightly moving from side-to-side. These represent different issues. Speed is also often a big factor in a car vibrating - the vehicle may start shaking as soon as it starts up, or perhaps only at highway speeds. Finally, shaking that only occurs when the car is slowed or coming to a stop typically indicates an issue with the brakes.
The suspension system is the first stop for many drivers when it comes to a shaky vehicle, but it's not necessarily the most common culprit. The suspension has a number of different parts, like shock absorbers, that are supposed to mitigate the amount of vibration the driver feels. Typically, if one of these parts are worn out, it will be an issue the driver feels constantly, rather than one that only occurs at high speeds.
Drivers also need to consider their steering system if the car begins shaking. A car's steering system is connected to the wheels through the tie rods. The wheels are among the most common causes for vehicle vibrations. Typically, drivers will feel this shaking in the steering wheel itself, since the wheels are connected to the steering system.
Wheel problems can be very simple, requiring balancing or re-alignment to fix. They may also indicate that an aspect of the wheel needs to be replaced, such as the bearings. If a wheel is completely bent, it will likely need to be replaced. Unfortunately, diagnosing wheel issues tends to require the car to be lifted off the ground so the wheels can spin freely. Since this is beyond the capabilities of most amateur mechanics, it's something best left to the experts.
In somewhat less common cases, the problem may be related to the engine itself. This is often the case if the car acts jerky or the shaking is at odd intervals. Spark plug misfires are the probable culprit in this case. Essentially, this means the plug is firing at the wrong time and causing the fuel to combust in irregular patterns. Not only does this result in a loss of performance, but it can do serious damage to an engine over time, so get this checked out right away.
If you suspect the issue is related to your brakes, there are a couple of specific parts of the brakes that may be at play. A warped rotor is probably the most common issue related to vibrations in the car, but it could also be caused by issues with the calipers. Worn brake pads can also cause braking issues, and may simply require replacing.