If your vehicle is shaking or vibrating when you are idle, it could be one of many different reasons. It could be something minor like a stray bolt or an engine misfire.
However, it’s important to address this issue as soon as possible, even if it seems minor, since it could be an indication of a more severe issue. Let’s briefly cover some of the possible reasons and how they can be an issue.
So Why Does My Car Vibrate When Idling?
In a properly running vehicle, the engine idles evenly and smoothly, meaning that proper air and fuel are mixing under ideal conditions.
In addition, the engine is producing a steady amount of power, enough to operate necessary systems such as the cooling system, power steering, air conditioning, and electrical systems, among others.
Vibrating when idling is typically due to rough idling. If your vehicle suffers from issues that cause pronounced vibrations or a ‘sluggish feeling’- traditionally known as rough idling- consider it an early warning system for your vehicle.
Your car is telling you there is an identifiable part that has failed or is on its way to failure and needs to be fixed sooner rather than later. Not correcting this issue may lead to being stranded or having to pay a lot of money for repairs.
Rough idling issues often accompany a poor performing vehicle i.e., poor fuel economy, hard time starting, high or low RPM fluctuations, and might lead to larger engine issues down the road.
Reasons Behind Car Shaking at Idle
Most modern vehicles today have internal computers or powertrains that utilize sensors to monitor and regulate systems throughout the vehicle to ensure all systems work properly.
The emissions system computes and monitors the combustion process and the exhaust system such that emissions stay within a predetermined limit.
When a system fails and goes outside predetermined limits or the vehicle experiences a rough idle, a check engine light will come on based on a code produced by the computer. The most common reasons for a rough idle include:
#1. Dirty Fuel Injectors.
Today’s vehicles are complex systems, and the overall goal is to create a vehicle that is as fuel-efficient as possible. One of the ways this is accomplished is through optimized fuel delivery from high-pressure fuel injectors, which provide the correct amount of fuel into the cylinder at the right time.
Fuel injectors operate at high temperatures and high fuel pressures and over time the fuel injectors’ tiny nozzles or pintles may accumulate carbon residue from the combustion process and become clogged.
If fuel injectors are obstructed, they cannot spray the right amount of fuel that is needed for combustion or if they cannot create the spray pattern needed to achieve proper combustion, hence poor performance and rough idle.
#2. Worn Spark Plugs, Wires & Ignition Coil.
For the combustion process to succeed, a spark needs to happen with the air and fuel mixture.
Each cylinder gets the spark by spark plugs, wires, and coils create the voltage for ignition. Worn or old spark plugs become dirty with oil or carbon deposits that greatly reduce the power produced by ignition.
By replacing your spark plugs every 30,000 to 50,000 miles you’re making sure you get a sufficient spark whatever the situation! You can also prevent damage to the electrodes that can cause severe damage to the ignition system in your vehicle.
Worn ignition components can also cause engine issues like rough idle. Just like spark plugs, poor performance of the ignition coil can lead to breakdown and misfire, triggering a check engine light and eventual rough idle.
#3. Clogged Air Filters.
As you drive down the road the engine air filter is catching all types of contaminants that could damage your engine. As filters fill with dust, dirt, and other particulate matter, the air flow becomes inhibited which is critical to allow for the proper air mixture for combustion.
Lack of air will now create a rich mixture that will increase fuel usage as well as create a rough idle.
#4. Vacuum Leak.
Under your car’s hood, the hoses we don’t think about help create the necessary vacuum for air and fuel, with some assistance from a throttle to regulate appropriate RPMs and needed air.
In the state of Arizona, it is rare that rubber hoses wear out or develop a leak. This creates a situation where the air-fuel mixture introduces too much air, which will cause an immediate misfire situation and result in a rough idle and increased RPMs.
#5. Oxygen Sensor.
The oxygen sensor is an emissions system component that measures how much oxygen is in the exhaust. This information is sent to the vehicle’s computer and is used to calculate the ideal ratio of air and fuel for the most efficient and clean combustion.
Many oxygen sensors can fail due to constant heat or carbon exposure or an older component. When the oxygen sensor fails, it sends incorrect information to the vehicle’s computer potentially causing the engine to run too rich or too lean resulting in rough idle.
#6. Motor Mounts.
The engine or motor mount supports the engine and dampens noise and vibration. It prevents noise and vibration from the engine and transmission from affecting the chassis and ultimately the rest of the vehicle.
Many motor mounts are fluid-filled and some are electronically actuated. Over time, the rubber-mounted insulation on the motor mount could wear out, or the entire motor mount could be damaged altogether, resulting in excessive engine vibration at idle.
If a motor mount is not replaced when damaged, it could cause other issues, such as overstressed components and wires, friction on drive belts and pulleys, and exhaust leaks.
#7. Faulty Idle Air Control Valve.
The idle air control valve controls engine idle speeds, preventing stalls when the engine load changes. If the idle air control valve is stuck closed, inoperative, or clogged with sludge, a low idle or rough idle is possible.
Idle air control is necessary to overcome the friction created in the engine from a cold lubricating oil state.
Additionally, the engine requires additional power in colder temperatures; the idle air control valve opens an intake air passage to provide additional air to the engine.
The idle air control system is also calibrated accordingly to generate a specified speed regardless of the operating temperature.
Damage to an idle air control valve can cause performance issues, and the vehicle may also experience issues like excessive vibration while idling.
#8. Fuel System Issues.
There are several parts in the fuel system that could cause your vehicle to experience excessive vibrations as it idles.
The first possibility is a dirty fuel injector. The fuel injector is exposed to boiling temperatures and high pressures, causing the pintle or nozzle to build up carbon, gumming it up.
If there is a stuck or clogged fuel injector, the cylinder the injector feeds won’t receive the correct amount of fuel. This can cause everything from a high-frequency shutter or shake to a moderately low-speed rough idle.
The next possible fuel system issue is a clogged fuel filter. Over time, a fuel filter can become contaminated, which will affect the flow of fuel combustion.
Another potential fuel system issue is a malfunctioning fuel pump. The fuel pump is responsible for sending the correct amount of fuel with proper pressure and volume to the engine while the vehicle is on the road.
In most cases a fuel pump fails under the wrong condition to produce air (cavitation), if the fuel system is return less, air bubbles will have to pass through the injectors and could cause misfires and rough idle.
A faulty fuel pump can also create issues such as hard starting, stalling, hesitation, and misfires.
My Car Shakes When I Hit the Gas
Just like when your car is idling, excessive shaking or vibration when you accelerate will usually be due to issues with the engine mounts. If they’re worn, damaged, or just loose over time, you will feel all the vibrations the engine produces every time you accelerate.
Some additional causes of shaking while accelerating may include:
- Misaligned steering system
- Loose/worn parts in the suspension system
- Engine misfiring
- Worn spark plugs
My Car Shakes When I Pick Up Speed
When you’re driving carefully and technically obeying the speed limit, you may have noticed your car shakes just a little more as you pick up speed.
Maybe even it’s while you are accelerating to merge on to the freeway or while you are passing someone on the interstate or while making that last minute exit. If this is the case you should really slow down and get your car into a shop to be check out.
Even slight shakiness while driving at higher speeds means something is not right. Your wheels could potentially be out of balance. This issue could be something related to alignment, but that is very unlikely. Either way, we recommend getting it repaired sooner rather than later and definitely before driving at higher speeds again.
Why Does My Car Shake When I Apply the Brakes?
On any vehicle, especially now, it is essential for our cars to stop safely and reliably, particularly when sudden emergency stops are required.
If your car shakes when you are braking, you may see your steering wheel shaking back and forth, your brake pedal pulsing, or maybe you just notice a large amount of noise and vibration coming from the front end of your vehicle.
It could probably be a combination of both. Shaking when you apply the brakes can feel scary, and lead you to lose confidence and perhaps leading to an accident. It’s best to have your car and brakes checked when you feel any kind of vibration when stopping.
Here are some possible culprits:
- Warped brake rotors
- Worn brake pads
- Damaged braking system