Car Shakes When Starting Then Runs Fine: 10 Causes & Easy Fixes

If your car shakes when starting then runs fine, then it can be both alarming and frustrating.

While it may seem like an issue that will lead to costly repairs or a full-blown breakdown, sometimes your vehicle runs just fine once it’s warmed up. 

In this article, we will delve into the possible causes behind this puzzling phenomenon, providing insight into the underlying mechanics, along with solutions to ensure a smoother start and extend the life of your vehicle.

Buckle up as we navigate this shaky situation and confidently get you back on the road.

Car Shakes When Starting Then Runs Fine


Car Shakes When Starting Then Runs Fine: Major Causes With Solutions

You’ve been driving your car for a while, and it’s been running fine. Then one day, when you go to start it up, the engine shakes violently before settling down into a normal idle. What happened?

The answer lies in understanding how an internal combustion engine works. When you turn over your key and press on the gas pedal, fuel is injected into cylinders, where it mixes with air before being ignited by spark plugs (or glow plugs).

This explosion pushes down on pistons which turn crankshafts connected to wheels via axles and gears–and voila! You’re off!

But what if there’s something wrong with this process of car shakes when starting then runs fine?

Loose Engine

A loose engine is when the engine shakes or rattles while driving. This can be caused by several things, including:

Loose Engine
  • Loose bolts or screws on your car’s engine
  • A faulty transmission (if it’s not working properly)
  • A bad fuel pump

Low Fuel Pressure

Low fuel pressure can be caused by several things, including:

Low Fuel Pressure
  • A faulty fuel pump or filter
  • Low-quality fuel that’s been contaminated with water or dirt (this is more common in older vehicles)
  • An improperly installed or damaged fuel line or filter.

Bad Spark Plug

A bad spark plug can cause your car to shake when starting, then run fine. A spark plug is a small piece of metal that ignites the fuel in an internal combustion engine, which then causes it to run.

If one of these pieces breaks or becomes damaged, it can cause your car’s engine will not start at all. In addition, if you have an old or worn-out spark plug that isn’t working properly anymore, this could also cause shaking when starting and running fine.

Bad Spark Plug

If your vehicle has been shaking when starting and then running fine due to bad spark plugs, and you want them replaced as soon as possible, contact us today! We’ll come out right away and get everything taken care of for you so that no further issues arise from this problem again in the future.

Dirty Fuel Injectors

If your car is shaking when starting but then runs fine, the problem may be dirty fuel injectors. Fuel injectors are responsible for spraying fuel into the engine.

If they’re clogged with dirt and debris, they won’t be able to spray enough fuel into the cylinders to keep them running smoothly while you’re driving. This can cause rough idling and stall and shaking during acceleration or deceleration–and sometimes even while idling at a stoplight!

Dirty Fuel Injectors

To fix this issue:

Try using a cleaner specifically for cleaning fuel injectors (like Seafoam). You’ll want one with an extra-thick viscosity that will stick around longer than other brands; otherwise, it might wash away before it has time to work its magic on those dirty little nozzles hidden inside your engine block!

Bad Motor Mounts

If you’re noticing that your car shakes when it’s started, then runs fine, the problem may be with the motor mounts. A bad motor mount can cause vibration and shaking in your vehicle when it’s first started.

The shaking will typically stop after a few minutes of driving, but if this happens often enough to annoy you or others who ride along, then it might be time for some new motor mounts!

Bad Motor Mounts

The causes of bad motor mounts include:

  • A worn out engine block (this is rare)
  • Excessive heat caused by poor maintenance or an overheating engine

Tire Issue

Tire issues can cause your car to shake when starting. If your tires are underinflated or worn out, this can cause the vehicle to vibrate and make it difficult for you to control the car.

Tire Issue

If you notice that one of your tires is damaged or flat, you must get it replaced immediately so that there is no further damage done to the tire or other components in your car’s suspension system.

You should also check all four tires regularly for signs of wear, such as cracking around sidewalls or uneven tread wear patterns across multiple tread grooves (this indicates overinflation).

Brake Problems

The brakes are one of the most important parts of your car. If you have a problem with them, driving can be very dangerous and could lead to an accident.

Brakes should always be checked regularly by a mechanic, but here are some things you can look for if you suspect something is wrong with your brakes:

Brake Problems
  • You hear noise from the front or back wheels when applying pressure on the brake pedal. This may mean an issue with either wheel bearings or calipers (the part that presses against the brake pads).
  • The pedal feels soft when pressed down–or even goes all the way to the floor before stopping! This could mean that air is in one or more tires; if so, try pumping them up until they feel firm again before driving anywhere else.* When stopping suddenly at intersections or stop signs (especially if there’s ice present), there’s a tendency for skidding rather than smooth braking due to inadequate friction between tires and road surface

Cold Weather

If you live in a cold climate and your vehicle is shaking when it’s cold outside, the problem may be a bit more complicated than just an engine tune-up. As you can imagine, a lot of things happen as soon as temperatures start dropping below freezing:

  • The oil becomes thicker and flows more slowly through the engine (this is why many cars recommend changing their oil at least once every 5K miles during winter).
  • The fuel mixture becomes less dense because of the lower air pressure at lower temperatures. This means that there isn’t enough oxygen to burn all of the fuel in each cylinder; some remains unburned and exit with exhaust gases,–which causes smoke to come out of your tailpipe when starting up after sitting overnight or longer!
  • To fix this issue, try adding a few ounces of gasoline conditioner into each tankful before starting up again (this will make sure everything runs smoothly).

Other Possible Causes

  • Air filter
  • Spark plugs
  • Ignition coil
  • Alternator
  • Battery
  • If you’re still having issues, it’s time to get serious. You’ll want to check your vacuum leaks and ensure nothing is loose inside the engine compartment. This could be anything from a loose hose or wire to a broken belt or pulley on your alternator or power steering pump.

How Do You Troubleshoot the Shaking Problem?

Troubleshooting a shaking problem involves identifying the root cause and taking corrective measures. Here’s a step-by-step guide:

  1. Observe the shaking: Note the circumstances under which the shaking occurs, such as specific speeds, terrain, or during acceleration or braking. This information can help narrow down potential causes.
  2. Inspect the tires: Uneven wear, improper inflation, or damaged tires can cause shaking. Check the tire pressure and ensure it’s within the recommended range. Look for bulges, cracks, or uneven wear patterns, and replace or rotate tires if necessary.
  3. Examine the wheels: Bent or unbalanced wheels can lead to shaking. Inspect for damage and have a professional balance of the wheels if required.
  4. Check suspension components: Worn or damaged suspension components, like shock absorbers or struts, can cause shaking. Inspect these parts for wear, leaks, or damage, and replace them as needed.
  5. Inspect the steering system: Issues with tie rods, ball joints, or the steering rack can cause shaking. Look for looseness or excessive play in these components and consult a mechanic for repairs.
  6. Investigate the brakes: Warped brake rotors or worn brake pads can lead to shaking, especially during braking. Inspect the brake system and replace any faulty components.
  7. Consult a professional: If the shaking persists after addressing these areas, it’s best to consult a professional mechanic for a thorough evaluation and diagnosis. 

Tips To Prevent the Problem of Car Shaking When Starting

  1. Regular maintenance: Keep up with your car’s scheduled maintenance, including oil changes, filter replacements, and tune-ups, to ensure optimal performance and prevent shaking issues.
  2. Inspect and replace spark plugs: Faulty or worn-out spark plugs can cause engine misfires, leading to shaking. Regularly inspect them and replace them as needed to maintain a smooth start.
  3. Clean the fuel system: Over time, fuel injectors and the throttle body can accumulate deposits, affecting engine performance. Use a fuel system cleaner and clean the throttle body to ensure proper fuel delivery and prevent shaking.
  4. Check engine mounts: Worn or damaged can cause excess vibrations and shake. Inspect them regularly and replace them if necessary.
  5. Maintain the ignition system: Check the ignition coil, distributor cap, and rotor for wear or damage, and replace them as needed to ensure a strong spark for smooth engine starts.
  6. Test the battery and charging system: A weak or faulty alternator can cause poor engine performance and shake. Regularly test your battery and charging system to ensure they’re in good condition.
  7. Inspect the air intake system: A dirty or clogged air filter can cause poor engine performance. Check the air filter regularly and replace it when dirty to maintain proper airflow.
  8. Monitor the exhaust system: A clogged or damaged exhaust system can result in shaking during startup. Inspect the exhaust system for damage or blockages and address any issues.
  9. Address warning lights promptly: If your car’s check engine light or other warning indicators come on, diagnose and address the issue quickly to prevent potential shaking problems.
  10. Consult a mechanic: If you notice any unusual shaking or vibrations when starting your car, consult a professional mechanic for a thorough inspection and diagnosis. Early detection and repair can help prevent more significant issues down the road.

Frequently Asked Questions (FAQs)

Why is my car shaking at a cold start?

A car shaking during a cold start could be due to various reasons, such as a malfunctioning fuel delivery system, ignition issues, or poor engine performance in low temperatures. It’s essential to diagnose and address the exact cause to prevent long-term engine damage and ensure a smooth start.

Can a bad starter cause your car to shake?

A bad starter can cause a car to shake if it struggles to turn the engine over properly, leading to uneven or slow cranking. However, shaking is not typically the primary symptom of a bad starter. A grinding noise, clicking sound, or failure to start are more common indicators.

Can old spark plugs make your car shake?

Yes, old or worn-out spark plugs can cause a car to shake. As spark plugs age, they may not provide a strong enough spark to ignite the fuel-air mixture efficiently, leading to engine misfires and shaking. Regularly inspecting and replacing spark plugs can help maintain smooth engine performance.


In conclusion, experiencing car shakes when starting, followed by normal running, can be attributed to various causes, such as faulty fuel delivery, ignition problems, or cold weather-related issues.

To maintain your vehicle’s performance and longevity, it’s crucial to promptly identify and address these problems. Regular maintenance, timely inspections, and consulting a professional mechanic when necessary will help keep your car running smoothly and prevent more significant issues from developing.

Stay proactive and attentive to your car’s needs to ensure a safe and enjoyable driving experience.

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