Typically, the car engine shakes and vibrates during acceleration. However, excessive shaking during acceleration is a clear indication of a problem. To resolve the issue, it is crucial to identify the root cause first.
So, what are the reasons why the engine shakes when accelerating? An engine misfire and broken motor mounts are the main reasons your engine will shake while accelerating. A failing dual-mass flywheel may also cause shaking when you accelerate. Diagnose each issue further to pinpoint the exact cause of the shaking issue.
The article aims to help you determine the issue behind your car’s engine shaking when you accelerate. Read on to learn the potential causes in detail and the steps to follow and fix them.
Why Does the Engine Shake When Accelerating?
Car engines are known to vibrate and shake when the car accelerates. The combustion process taking place in the engine increases during acceleration due to the increased power demand.
These vibrations are usually felt through the steering and mildly in the cabin. However, the vibrations and shaking are more intense if there’s an issue with engine parts.
In this case, you need to diagnose the vehicle further to determine the issue behind the vibration. However, there are the usual culprits, which are usually the parts you should check first.
The following list contains the reasons the engine shakes when accelerating;
1. Cracked Motor Mounts
Cracked motor mounts, also called engine mountings , are one of the likeliest reasons behind your car engine shaking when accelerating. Motor mounts are components that hold the engine to the frame of the vehicle.
With time, the rubber part of the motor mounts cracks, and the mounts loosen, which allows the engine to vibrate while running.
Diagnosis
To confirm the motor mounts are the main reason behind the shaking, perform the following diagnostic tests.
- Locate the motor mounts on your car. They’re usually on either. side of the engine. (consult the user’s manual). Access the motor mounts and check the rubber parts for cracks.
- Get someone to press the gas pedal while you observe the engine. The motor mounts are probably broken if the car engine moves forward or backward.
Solutions
The solution to broken engine mounts is to replace them. Follow the steps below to replace the mounts.
- Step 1. Support the engine.
- Step 2. Unscrew the motor mount and remove it (do it one at a time).
- Step 3. Install the new motor mount and screw it on.
Here is a video showing how to replace the mounts.
Motor mount replacement will cost you between $400 and $1000. The cost varies with the car type.
2. Engine Misfire
Another reason your car engine shakes a lot when accelerating is due to a misfire. An engine misfire happens when normal combustion does not take place during the compression stroke.
Misfire disrupts the combustion process, and the power imbalance from the cylinder causes the engine to shake. Since during acceleration, there’s high power demand, the imbalance is more noticeable, and the shaking is severe.
The various reasons behind a misfire include a worn-out spark plug, a damaged ignition coil, and a faulty fuel injector.
Diagnosis
To confirm a misfire is the reason behind the shaking when accelerating, check for the following signs and symptoms.
- The vehicle is sluggish when accelerating
- Unusual sounds from the car engine
- Illuminated check engine light
- Dark and thick exhaust
- Low gas mileage
- No clicks when testing the fuel injector with a long screwdriver
The following video shows how to test the fuel injector.
Solutions
The solution to an engine misfire is to repair or replace the part causing a misfire. The following are steps to repair or replace the car parts mentioned above as the potential causes of a misfire.
- Spark Plugs
Purchase a spark plug compatible with your vehicle and follow the steps below to replace it;
- Step 1. Disconnect the wires (ignition cables) connecting to the spark plugs.
- Step 2. Use a socket wrench to pull out the spark plug.
- Step 3. Install the new spark plug and tighten it with a torque wrench.
- Step 4. Replace the ignition cables.
The spark plug replacement will cost you between $70 and $380, labor costs included.
The following video shows how to replace spark plugs.
b) Ignition Coils
Purchase ignition coils and follow the steps below to replace them.
- Step 1. Turn off the vehicle and allow it time to cool.
- Step 2. Disconnect the car’s battery ground wire (usually black).
- Step 3. Unplug the ignition coil plugs.
- Step 4. Unscrew the ignition coils and gently pull them off.
- Step 5. Install new ignition coils and screw it back on.
- Step 6. Plug the ignition coil plugs.
- Step 7. Connect the battery ground wire.
- Step 8. Test
Replacing ignition coils costs between $100 and $310 each. The price varies with the car type and repair shop.
Right below is a video showing how to replace ignition coils.
c) Fuel Injectors
After purchasing a fuel injector compatible with your vehicle, follow the steps below to replace it;
- Step 1. Turn off the vehicle and allow it time to cool. Also, disconnect the negative terminal of your car’s battery.
- Step 2. Unplug the fuel injector connectors.
- Step 3. Using a socket, unlock the fuel rail.
- Step 4. Wiggle the injectors off.
- Step 5. Clean the injectors with an injector cleaner of your choice.
- Step 6. Install the clean or new injectors.
- Step 7. Lock the fuel rail.
- Step 8. Plug the fuel injector connectors.
- Step 9. Connect the car battery.
Replacing fuel injectors cost between $300 and $1000. The price varies with car type and the repair shop.
The following video shows you how to replace the fuel injectors.
3. Dual Mass Flywheel Issues
A damaged or faulty dual mass flywheel (DMF) may also be behind the issue of the engine shaking while accelerating. The DMF dampens the engine vibrations and shaking, preventing interference to the drivetrain.
The dual-mass flywheel can get faulty as it ages, and the springs or dampers inside get faulty. Also, various components in this component, like the springs, dampeners, and the housing, can become loose or damaged.
Diagnosis
To confirm the DMF is behind the engine shaking while accelerating issue, perform the following diagnostics;
- Check for failing clutch symptoms like slipping, grabbing, and vibrations when engaging and disengaging it.
- Access and visually inspect the DMF. Listen for noises it is making.
Solutions
A problematic DMF can be repaired or replaced. However, this is a complex and labor-intensive operation. Repairing or replacing the DMF involves removing the transmission and other car components. This fact makes the replacement complex and a labor-intensive task.
Therefore, hire a professional to repair or replace the DMF for you. This replacement is expensive and will cost you between $900 and $2,000.
Why Does Your Engine Move when Shifting?
It’s entirely normal for an engine to exhibit movement when shifting gears. Typically, a slight inch or two of movement is within the acceptable range. The concern arises when this movement is accompanied by loud, harsh clunks, signaling potential issues with the engine mounts—essentially the shock absorbers for the engine.
The engine’s natural vibration intensifies during gear shifts due to load changes from the transmission. While the engine mounts, often rubber bushings, dampen these vibrations, they wear out over time.
If you’re not hearing concerning noises, there’s likely no immediate worry. Comparing your car’s movement and sound to another of the same model or seeking repair cost estimates can help gauge the situation. In essence, engine movement alone, within a certain range, is considered normal and nothing to be overly concerned about.
If your vehicle experiences engine shaking when accelerating, you might find our articles on ‘Engine Vibration When Decelerating: Know The Causes And Solutions’ and ‘The Car Engine Shakes When Starting – What to Do?’ beneficial, encompassing all the necessary information. Our comprehensive exploration of engine vibration when decelerating delves deep into the intricacies of this issue, elucidating the underlying causes and offering practical solutions to alleviate the problem. From worn-out engine mounts to fuel system irregularities, we cover it all, ensuring you’re equipped with the knowledge to tackle this concern effectively. Furthermore, our detailed analysis of engine shakes when starting leaves no stone unturned in providing you with essential insights. Whether it’s a matter of ignition system malfunction or issues with the fuel injection system, we guide you through the diagnostic process, empowering you to address the root cause of the engine shaking phenomenon. With our step-by-step troubleshooting guide, you’ll be able to identify and resolve the issue with confidence, ensuring optimal performance and smooth operation of your vehicle. Explore these articles today to gain a comprehensive understanding of engine shaking issues and equip yourself with the knowledge needed to keep your vehicle running smoothly.
Related Questions
The following sections list questions people ask about the car engine shaking when accelerating.
Q1. How Long Do Engine Mounts Last Before They Seize Allowing The Engine to Shake?
In most cases, the engine mounts should last more than 5 years and can last up to 10 years. However, this lifespan is only possible if the vehicle is driven most of the time on even roads.
Q2. Why Does Engine Shake Only When Accelerating But not When Coasting?
Engine shakes mostly when accelerating due to the increased operations as the car accelerates. When coasting, the engine demand is low and you’ll barely feel the shaking.
Q3. Front End of The Car Shakes When Accelerating?
When the front end of the vehicle shakes when accelerating, it usually shows an issue with the engine. Most of the time the engine is the source of the shaking but broken CV joints and misaligned wheels.
Final Thoughts
If your car’s engine shakes when accelerating, check for damaged motor mounts or misfires. A faulty DMF may also be behind the shaking as the vehicle accelerates. Diagnose each issue further and provide the necessary fixes. The article lists various steps you can follow to fix the issues behind the shaking. However, some of the solutions are complex and labor-intensive, and you should get a professional to handle them. Also, if you are uncomfortable diagnosing and fixing the issue, take your car to a repair shop