Hey, Why Is My Car Shaking When Stopped?

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Four common causes for a vehicle shaking while stopped and their related parts.
When your vehicle’s engine is operating efficiently, all cylinders contribute equally. There can be many reasons for a cylinder to under-contribute or over-contribute, which will cause the vehicle to start shaking. The shaking is an indicator that there is something that is not balanced out or that there is something that is touching that shouldn't be touching. Nevertheless, when you feel the vehicle shake, something is failing and you should consult with a professional.

Is Your Car Shaking While Stopped?

It commonly shakes when stopped because of loose or damaged motor mounts. However, it can also be fuel flow problems that are overstressing the engine, such as carbon deposits, faulty fuel injectors, leaking intake valves, or damaged spark plugs.

If you're experiencing your car trembling when it comes to a halt, taking action is essential. This occurrence may be a symptom of an underlying problem that warrants your attention. While it may appear minor, the shaking can affect your vehicle's handling and performance, threatening road safety.

To prevent further damage and expensive repairs, it's vital to act promptly and consider having a vehicle health inspection. By doing so, you can rest assured that your car will be safe to drive and won't pose any danger to yourself or others on the road.

Let's Get To The Bottom Of It!

  • Q: Is the "check engine" light permanently active on the dashboard?

    The engine must track and control incoming air to work correctly and reduce pollution. It uses sensors to measure how much air is coming in and mixes it with fuel for efficient combustion. However, if air leaks into the engine from somewhere else (like a faulty intake gasket), the sensors will detect it and report it to the engine's computer. This will cause the "check engine" light to turn on, alarming you about a problem. This can also cause a "lean" condition, which means there isn't enough fuel in the mixture, which can cause engine damage over time.

  • Q: Is the engine sputtering and shaking when the car is idle?

    Fuel injectors are tiny nozzles spraying fuel into the engine's cylinders. The amount of fuel and timing of the spray is controlled electronically by the engine computer's drivers. If the electrical part of the injector fails, it won't spray any fuel into the engine, causing a "lean misfire." This means there's too little fuel in the air going into the engine, making it sputter and shake at idle. If a single injector fails, the sputtering and shaking might be unnoticeable while you're driving since the car's momentum keeps it shy. However, the engine shakes and sputters noticeably when you stop or idle.

  • Q: Is the engine shuddering and shaking noticeably in cold weather?

    The engine valves have an important job. They must open and close at the right time to allow fresh air into the engine and maintain the correct pressure during combustion. They also need to let combusted air out during the exhaust phase. Over time, the engine part where the exhaust seats stand may wear down. This happens because the exhaust seats are rigid while the engine head is softer aluminum. As a result, the exhaust seats can be forced into the head, causing the valve to stay partially open when the engine is cold. This makes the engine shake and misfire. However, once the engine heats up, the head expands enough to close the valve and stop the misfire.

  • Q: Have you noticed a drop in the vehicle's fuel economy?

    In modern direct injection engines, there's a tendency to accumulate carbon buildup and deposits. This happens because oil vapors from the crankcase don't wash away the carbon buildup from the valves and cylinder. However, engines that mix fuel with air do not have this issue. As the carbon buildup on the cylinder and valves increase, it blocks airflow, reducing the engine's efficiency and consuming more fuel. This leads to a decrease in the engine's fuel economy.

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Vehicle Health Inspection Proof

Explore the following typical inspection results that show a potential cause for the symptom and select the one you believe is similar to your vehicle's issue.

Leaking intake valve

The proof image shows the needle on the vacuum gauge jumping, indicating an inadequately sealed valve.

A customer dropped off their vehicle and explained that the check engine light would flash this morning while the car shuttered and shook. Then, after the car warmed up, the engine ran okay, and the check engine light stopped flashing.

During a test drive, the technician didn't notice anything related to the customer's concern, but they did see the check engine light on. After a vehicle health inspection, the technician found no issues related to the customer's problem.

However, when doing a code scan, they found multiple misfire codes: a P0300 random misfire, a P0301 cylinder one misfire, a P0303 cylinder 3 misfire, and a P0305 cylinder 5 misfires detected.

The technician was authorized to conduct additional diagnostics to diagnose the problem further. First, they used a vehicle-specific scanner and verified the misfire codes. Next, they checked the live misfire data and found very high misfire codes stored on "Bank One." Plus, there were stored random misfires on Bank 2, but none occurred.

To investigate further, the technician left the vehicle overnight and checked the misfires at the first startup the next day. They utilized a vacuum gauge along with the live data from the scanner. They found that the vacuum gauge fluctuated almost four inches of mercury at idle while the misfires were happening. This indicated that the valves were not sealing when the engine was cold.

The technician recommends that the valves be adjusted and retested for misfire codes on cold startup. If the misfires continue on cold startup, the heads will need to be removed, and a valve job will need to be performed on the heads.

Does the issue look like this? if not accessible your shop will document it
Carbon deposits

The proof image shows the carbon deposits inside the engine that are causing a reduction in fuel economy. By addressing this issue, the car should run more efficiently, and the customer should see an improvement in fuel economy.

A customer brought in their car concerned their fuel economy decreased. Plus, they suspected that either a tune-up was needed or the fuel economy gauge was faulty.

During the test drive, the technician did not notice anything unusual. Additionally, the vehicle health inspection found no issues related to the customer's concern.

The customer authorized additional diagnostics, and the technician used a specialized scanner to check for any codes. However, no codes were found, so the technician checked the live data while the engine ran.

They found that the engine was overworking and struggling for air when the car was idling, indicating a problem. The technician double-checked the air filter and found it was clean.

Next, the technician removed the spark plugs for inspection and discovered carbon buildup on them. They also checked the valves, pistons, and cylinder with a borescope and found the same buildup. This issue was likely causing the engine to work harder and burn more fuel than necessary.

The technician recommended a direct fuel injection service and decarbonization to fix the carbon buildup.

Does the issue look like this? if not accessible your shop will document it
Vacuum leak disrupting engine performance and causing the check engine light to come up on the dashboard

The proof image shows the location of the vacuum leak at the intake gasket.

A customer dropped off their vehicle because they noticed a high idle when starting the car in the morning. Also, they mentioned the check engine light had been on for about a month.

During the test drive, the technician found that the check engine light wasn't flashing anymore, and nothing else seemed to be related to the customer's concern.

However, during the vehicle health inspection, the technician found two error codes, P0171(the system is too lean on bank 1) and P0174 (too lean on bank 2). This prompted the technician to request authorization for additional diagnostics, which the customer agreed to.

Using a vehicle-specific scanner, the technician verified the lean codes and checked the fuel trims at idle. Finally, they found enough evidence of a vacuum leak.

To find the source of the leak, the technician blocked off the intake at the mass air flow sensor and injected smoke inside it. Then, the smoke came from the intake gaskets, meaning they would need to be replaced.

Does the issue look like this? if not accessible your shop will document it
Faulty fuel injector

The proof image shows a noid light installed by the technician in the fuel injector connector, which proved the injector failed. This caused an engine shaking issue.

A customer dropped off their vehicle concerned that the car seemed like it was going to die when idling. They also mentioned that the check engine light was on and sometimes flashed.

During a test drive, a technician confirmed a miss at idle and that the check engine light was on. The technician conducted a vehicle health inspection to investigate the issue further but found nothing related to the customer's concerns.

However, after a code scan, they found a code indicating a cylinder three misfire. The customer authorized additional diagnostics, and the technician used a dedicated scanner, confirming that cylinder 3 was misfiring.

The technician then inspected the spark plug and coil for cylinder 3 and found them in good shape. Next, they performed a compression test on the cylinders and found that they were all within 10% of each other.

To further diagnose the problem, the technician moved the spark plug for cylinder 3 to the number 1 hole and switched two coils with the number 3 coil. They cleared the codes and restarted the car, but cylinder 3 was still misfiring.

Next, the technician unplugged the electrical connector to the number 3 injector and used a noid light to check if the ECM sent a signal to pulse fuel. After verifying that the ECM was sending a signal to the number 3 injector, the technician switched the number 3 and number 2 injectors and found that the misfire had moved to cylinder 2.

This indicated that the injector on cylinder 3 had failed electronically and needed to be replaced.

Does the issue look like this? if not accessible your shop will document it
Faulty spark plug

The proof image shows leaked oil, which is the reason the car has worn spark plugs, causing the engine to misfire.

A customer dropped off their vehicle and mentioned that the check engine light had been on for some time and was now red and flashing.

During the test drive, the technician noticed that the vehicle was misfiring and the check engine light was still flashing. However, during a vehicle health inspection, the technician saw no issues related to the customer's concern.

To determine the cause of the misfiring, the technician used a vehicle-specific scanner to scan the vehicle's computer and found a P0302 code, which means that cylinder 2 was misfiring.

The customer authorized additional diagnostics, and the technician observed live misfires on cylinder 2, confirming it was consistently misfiring. Upon further inspection, the technician found that the spark plug in cylinder 2 was oil-ridden, while the others were not.

To verify the engine's condition, the technician performed a cylinder leak-down test on cylinder 2, which showed that the leak-down percentage was less than 10%. This means the rings in cylinder 2 were sealed properly, but the valve seals on cylinder 2 failed. As a result, the technician recommended replacing the spark plug wire, bodies, and all valve seals in cylinder 2.

Does the issue look like this? if not accessible your shop will document it
Torn torque motor mount

The proof image showed that the torn rubber in the upper torque mount was the cause of the shaking and clunking noise heard when shifting gears.

A customer brought their vehicle to the shop, concerned the car was shaking unusually while idling. They also noticed a strange noise from under the hood when shifting gears.

During a test drive, the technician confirmed that a clunking noise came from the engine bay when shifting between forward and reverse. However, the technician found nothing related to the customer's concerns during a vehicle health inspection.

To investigate further, the technician had an assistant start the vehicle while pressing the brakes with the emergency brake pulled. The technician then had the assistant shift the car between drive and reverse while torquing the engine attached. The technician noticed the engine rotating back and forth at this point and discovered that the upper engine torque mount was torn.

In addition, the front engine mount and both side mounts were sagging and transferring engine vibration to the chassis. As a result, the technician concluded that replacing the broken motor mounts was necessary.

Does the issue look like this? if not accessible your shop will document it

Typical Fixes to Address the Cause(s)

The following chapters bases themselves on experiences from our auto repair shop; we'll describe related problems' causes and fixes.

"Spark plug replacement" fixes "Faulty spark plug"

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Hey, Why Is My Car Shaking When Stopped?
Sometimes a problem is more challenging to describe than it initially looked like. If you are not sure your problem is described by this article, please find below similar vehicle symptoms, which might describe better the issue you are experiencing.

Other things your auto repair shop might talk about:

Fuel intake system. Car shakes. Vacuum hoses. Steering wheel. Timing belt. Rough idle. Fuel system. Brake rotors. Transmission mounts. Brake pedal. car shake. poor fuel economy. intake manifold. engine speed. car vibrate. warped brake rotors. brake pads. ignition coil