A Mechanic’s Answers to Your Questions

Feeling your car shake while driving is, on its own, an uncomfortable and alarming experience. A bumpy ride can happen while accelerating, braking, idling, or even when you’re parked. Not knowing why your car is shaking can be even more stressful.

Our experienced mechanics are here to answer the most common questions about why your car might be shaking and what you can do about it.

Why is my car shaking when I accelerate?

Shaking during acceleration often indicates issues with your vehicle’s drivetrain, wheels, or engine components. Common causes include:

• Damaged or unbalanced tires: Unbalanced or worn tires can cause vibrations that intensify as you speed up.
• Bent axle or driveshaft: If these components are bent or damaged, you’ll feel shaking that worsens with acceleration.
• Worn CV joints: Constant velocity (CV) joints transfer torque from the transmission to the wheels. A worn CV joint often produces a clicking noise alongside shuddering during acceleration.
• Loose lug nuts: Wheels that aren’t properly secured with lug nuts can wobble under stress, becoming more dangerous at higher speeds.
• Broken motor mounts: These mounts keep the engine stable. If they are broken, your engine will be able to move around, which can cause vibrations when idling that get worse when you accelerate.
• Engine issues: Faulty spark plugs, dirty fuel injectors, or misfiring cylinders can cause the engine to stumble, creating a jerking sensation when you press the gas pedal.

So what can you do?

If your car shakes when accelerating, it’s typically not a problem you can fix on your own. Have it inspected and repaired promptly to prevent further damage.

Why is my car shaking when I brake?

Shaking while braking is usually related to your braking system or wheel components. The most common reasons are:

• Warped brake rotors: Over time, rotors can become warped or uneven, causing the brake pads to grip inconsistently and create a pulsating or shaking sensation.
• Worn brake pads: Thin or unevenly worn pads fail to grip the rotor evenly, leading to shakiness.
• Stuck brake calipers: A sticking caliper can cause uneven application of pressure to the brake pads, making the car pull or vibrate during braking.
• Unbalanced or worn tires: When unbalanced, worn, or unevenly worn tires make contact with the road, they can cause vibrations when braking.
• Poor wheel alignment: Misaligned wheels can cause uneven braking force across tires, making the car vibrate or pull to one side when stopping.

So what can you do?

Failures in your braking system can have dangerous repercussions. If you notice shaking when braking, have your vehicle checked as soon as possible.

Why is my car shaking when I drive?

General shaking while driving can stem from several different issues:

• Unbalanced or worn tires: Tires are one of the most common sources of car shaking. When unevenly worn tires make contact with the road, it can cause shaking throughout the entire vehicle.
• Damaged wheels or rims: Even a slightly bent rim can disturb your tire’s rotation, creating noticeable vibrations through the steering wheel and cabin and causing damage to your tires.
• Loose lug nuts: Loose lug nuts can make your car’s wheels wobble, which creates a shaking sensation. Lug nuts keep your wheels secure on your vehicle, and when they are loose, your wheels can fall off. Get them tightened as soon as possible to avoid any unnecessary hazards.
• Suspension or steering issues: Failing ball joints, bushings, tie rods, or steering rack issues can cause unstable steering and car shaking.
• Wheel alignment problems: Misalignment can lead to uneven tire wear and, over time, cause vibrations.

So what can you do?

Getting regular maintenance and routine inspections can help you prevent or diagnose and resolve these common causes of car shaking.

Why is my car shaking while idling?

Or, in other common terminology, you could also be asking yourself, “Why is my car shaking when I stop?” or “Why is my car shaking when parked?”

However you phrase the problem, if your car shakes while idling (when it’s on but not moving), it typically points to engine or mount problems. Common causes include:

• Engine misfires: Faulty spark plugs or bad ignition coils can cause uneven combustion, leading to engine vibration.
• Broken or weak motor mounts: Motor mounts secure your engine and transmission. If worn or damaged, they fail to absorb normal engine vibrations, which you’ll feel more strongly when idling or at a stop.
• Vacuum leaks: A leak in one of the engine’s many vacuum lines can cause the engine to run lean (too much air, not enough fuel), leading to rough idling and shaking.
• Dirty fuel injectors or air filters: Restricted airflow or fuel flow disrupts the combustion process, causing your car to shake when stationary.
• Accessory loads: When accessories like the air conditioner, defroster, or headlights are on, they place additional load on the engine. If the engine is weak or poorly tuned, these loads can cause it to shake while stopped or idling.

So what can you do?

Persistent shaking when stopped or parked means it’s time for an inspection. Proper diagnostics from a mechanic can pinpoint the exact problem, whether it’s a simple tune-up or a more involved repair.

Why is my car shaking when I turn it on?

Shaking right after starting your car is often related to engine or mount issues:

• Engine misfire: Problems with spark plugs, ignition coils, or wiring can cause a rough, shaking start.
• Worn motor mounts: When damaged, the mounts can’t properly absorb engine vibrations, leading to shaking.
• Fuel or air delivery problems: Dirty fuel injectors or air filters can cause rough starts and vibrations.

So what can you do?

Some shaking during startup is normal, especially in cold weather and subfreezing climates like winter in Fairbanks. However, if you notice more shaking than usual or if the shaking persists after startup, get your vehicle inspected.

Why is my car shaking when I drive fast?

Shaking at highway speeds points to problems exacerbated by higher rotation speeds, such as:

• Unbalanced wheels or tires: Centrifugal force magnifies even small imbalances at higher speeds, which can cause noticeable shaking.
• Worn or damaged tires: Uneven tread or out-of-round tires (due to poor manufacturing, wear, or storage) can cause significant vibration at highway speeds.
• Bent wheels or axles: Bends, even if not visible to the eye, cause imbalances that worsen with speed.
• Suspension or steering issues: High-speed forces put added strain on worn ball joints, bushings, or tie rods, revealing shaking issues that might not be obvious at lower speeds.

So what can you do?

If your car shakes at highway speeds, take your car into the shop as soon as possible to have your tires, wheels, steering, and suspension checked. If left unchecked, you could lose control of steering on the highway.

Keep Your Car from Shaking with Preventive Maintenance from an Expert

Car shaking can be caused by a variety of issues, ranging from simple tire imbalances to more serious engine or brake problems. 

One of the best things you can do for your vehicle is to get it regularly inspected and professionally maintained. Consistent care can help prevent a lot of the issues that lead to car shaking. However, if you experience persistent shaking, it’s best to have your vehicle inspected by a professional to ensure your safety and prevent further damage.

At Metropolitan Garage, we focus on preventative car care, catching minor issues before they become major problems. Need maintenance? Schedule an appointment today.