Car Shakes When Starting Then Runs Fine

Car Shakes When Starting Then Runs Fine: Reasons and Solutions

The problem of a car shaking when you first start is common among many cars and car models. Despite affecting vehicles in all locales, it is more on automobiles in colder regions. 

But why does the car shake when starting then runs fine? The shaking during the start-up problem points to a loose part or combustion problems. Either the engine mounts are loose, or the fuel pressure is low. Worn-out spark plug and low coolant temperature can also be the cause.

The shaking can be unnerving, and even though it stops after some time, it needs checking. Read on to learn the possible causes of vehicle shaking and how to repair it.

Why Does Car Shake When Starting Then Runs Fine?

This problem has many causes, most of which revolve around the engine and its performance. Below, we have addressed some of these causes and their solutions.

Why Does Car Shake When Starting Then Runs Fine

1. Loose engine

The engine mounts hold it in position and ensure steadiness when it runs. Most engine mounts contain metal and rubber, which can wear over time, allowing the engine to vibrate freely.

However, to be sure the cause is the engine motor mounts, observe for other symptoms, like impact noises.

Loose engine

Solution

The problem requires a professional to fix since it involves interacting with the engine. The mechanic should replace the mounts with new ones.

2. Low Fuel Pressure

Fuel in the system contains pressure, so it moves where needed first enough. If the pressure is insufficient, the engine might receive incorrect fuel and air ratio, causing problems. 

The reason why this problem is only after starting is that the fuel pressure adjusts shortly after starting. Among the common causes of low pressure in a fuel system are leakages.

The fuel tank, fuel injector, or the vehicle’s pressure regulator might be the cause. 

Low Fuel Pressure

Solution

To repair, you should first locate the leaking point. Repair involves replacing the failing part with a new one.

3. Low Car Battery

Vehicles draw the first power from the battery so the engine can run. If the battery is low on juice, it might be unable to start the car engine properly and cause a shaking problem.

Low Car Battery

Solution

Replace the faulty car battery with a new working one. And replacing the battery is not difficult and should be doable by following the user manual.

Read:  Why Is My Car Shaking After Battery Change? (How To Fix?)

4. Bad Spark Plug

The spark plug creates a spark in the engine during the combustion stroke. If the spark plug has a fault, it’s unable to create a spark and cause a misfire. A misfire can trigger the shaking problem.

Bad Spark Plug

Solution

Spark plugs are easy to replace by following your vehicle’s user manual. You can buy new spark plugs at any vehicle part store or order online. A new one costs between $15 and $100.

What Are the Early Symptoms of the Car Shaking Problem?

The shaking after starting problems can cause costly damage to the vehicle if not noticed and fixed on time. You can tell the problem by observing some early symptoms. These symptoms include; 

What Are the Early Symptoms of the Car Shaking Problem

1. Check Engine Light Illuminates

The engine light illuminates when the engine has a problem. You should not ignore the light as it can be an early sign of loose engine mounts.

Check Engine Light Illuminates

2. Leakage

If you notice fluid under your vehicle, it might be coolant or fuel leaking. Take your car to be inspected and fixed, which can stop the shaking problem before it develops. 

3. Car Runs Rich

A faulty fuel pressure regulator can cause the engine to run rich and produce black smoke. Since low pressure is one of the causes of the car shaking on startup, fix the regulator soon.

Car Runs Rich

4. Error code

If you get an engine misfire trouble code after scanning the vehicle with an OBD scan tool, correct it soon. Misfire can be from the spark plug and, if not replaced on time, can cause shaking.

How Do You Troubleshoot the Shaking Problem?

It’s better to troubleshoot the shaking problem as soon as you face it. There are ways to troubleshoot this problem, as shown below.

How Do You Troubleshoot the Shaking Problem
  • Jumpstart your vehicle with a new battery if yours has discharged
  • Cycle the key on the ignition several times before attempting to start, which improves the oil pressure
  • Refill fuel to make sure the pressure is enough
  • Use a scan tool to learn engine problems

Tips To Prevent the Problem of Car Shaking When Starting

Why Does Car Shake When Starting Then Runs Fine

The shaking problem is costly and takes much time to diagnose and repair. Therefore, like most other car problems, they should be avoided if possible. The tips below will help prevent the problem.

  1. Service the engine regularly and make sure the mounts are holding
  2. Check for leakages and do any repairs on time 
  3. Scan the engine to learn of any misfires
  4. Observe the engine performance regularly in case of a failing spark plug
  5. Service the vehicle regularly and on time
Tips To Prevent the Problem of Car Shaking When Starting
If your car shakes when starting then runs fine, you might find our articles on car shaking after oil change and car shakes when braking helpful. Our article on car shaking after oil change explores some of the common reasons why this issue can occur, such as overfilled or low engine oil levels, a clogged oil filter, or using the wrong oil viscosity. Meanwhile, our article on car shakes when braking discusses how warped brake rotors, worn brake pads, or suspension issues can cause shaking while braking. Be sure to check out our resources on car shaking after oil change and car shakes when braking for more information.
Read:  Car Shakes When Stopped (This is How You Fix It)
Car Shakes When Starting Then Runs Fine

FAQs

The following are some frequently asked questions people ask related to this topic.

Q: What Is the Repair Cost for A Car That Shakes When Starting and Runs Fine?

The repair cost for a vehicle that shakes after starting but runs fine depends on the cause. However, the cost can range between $200 and $1500, labor included.

Q: How Long Does It Take to Diagnose a Car That Shakes When Starting?

The time to diagnose the shaking problem depends on whether you have other supportive symptoms. However, a professional mechanic can take between 45 minutes and two hours to diagnose.

Q: Can You Repair a Car That Shakes When Starting?

Yes, if the cause doesn’t require many repairs, like replacing a spark plug. However, if you’re unable to tell the reason or repair, you might need to visit a repair shop.

Bottom Line

The problem where the car shakes after starting but then runs fine has various causes. The causes are mainly a loose engine mount or low fuel pressure. Solutions include replacing the faulty motor mounts and correcting the fuel pressure.

To pinpoint the problem, you can attempt troubleshooting the problem. Observe the earlier symptoms of this problem to provide solutions on time. Besides, the tips in the article should help you prevent the shaking problem.

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