Nothing gives you more anxiety when your vehicle starts doing something it hasn’t before, including the car shaking when accelerating.
There are numerous reasons for imbalanced wheels, worn out CV-joints, loose lug nuts, and much more.
This article will cover the 12 causes of a car shaking when accelerating.
- 12 common causes for a car to shake when accelerating
- Final thought on cars shaking when accelerating
12 common causes for a car to shake when accelerating
1. Wheel imbalance
This is the biggest cause of vibration and shakes when accelerating and becomes worse the faster you go.
There can be two ways the wheels have become imbalanced, you might have changed your tires lately and the shop might not have balanced your wheel properly or a wheel weight fell off.
A wheel weight falling off is quite common since they are stuck onto the barrel of the rim these days instead of the older method of hammering on weights on the edge of the rim.
The quality of the double-sided tape used on the weights is also a big factor as they will easily fall off if it is cheap double-sided tape.
2. Bent wheel
This will usually be felt after you struck a significant pothole at speed, this is a harsh hit, so not pleasant at all.
Keep in mind that the wheel can be bent on the inside so it won’t be visible when you inspect it from the outside, you will have to look underneath the vehicle.
Steel wheels have a greater chance of bending while steel is more malleable than an alloy or magnesium wheel which is more prone to tear or shatter.
3. Imbalanced or damaged driveshaft
Between the two the most violent shake is from a (propeller) driveshaft (the shaft between the transmission and the differential) on a rear-wheel drive, four-wheel drive, or four-by-four vehicle since it is long and weighs a lot more than a side-shaft (the shaft between the differential and the wheel).
Since the driveshaft is so long it also needs balancing, the weights usually don’t fall off since they are welded on but even a small dent can cause a major imbalance.
The shake or vibration is the same as with wheel imbalance, the faster you go the worse it gets but with the driveshaft, you will be able to see and feel it through the gear lever.
Side shafts are noticeable and also get worse the faster you go.
Other than the propeller shaft the side shafts will not get a dent but rather bent since they are solid metal.
4. Worn out CV joints
Connecting the side shafts to the wheel hub and the differential is 2 CV joints and if they are worn out they can lead to clucking sounds and vibrations when driving and accelerating.
A telltale sign of a CV joint that needs attention is the rubber boot, which conceals the joint itself, with grease inside having a tear or is gone.
When water and dirt enter the CV joint and most of the time the grease escapes, leaving a messy greasy mess around the differential or the wheel hub, the CV joint then starts wearing out since the foreign material eats away at the bearing surfaces inside until it fails.
5. Worn-out engine mounts
While not entirely vibrating or shaking, worn-out engine mounts can result in quite a drastic clucking or just a violent shake between gear changes.
You need to think that the engine will only move when the throttle is applied and will settle as the revs rise (as the torque drops off).
An easy way to test if your engine mounts are done is to ask a friend to look under the hood while you keep the handbrake engaged and try to pull away, due to the increased torque needed to move the engine will move drastically (easily 1 to 2 inches, or 2,5 to 5 cm) if a mount is damaged.
6. Ignition problems
This ranges from sparkplugs, coil packs, and sparkplug wires for the older design engines.
Sparkplugs only have a certain lifespan and are also seen as a service item and if your sparkplug can’t ignite the fuel properly it will result in hesitations and jerkiness that can give you the feeling of the vehicle vibrating.
Coilpacks also can result in inefficient combustion when it is damaged or worn out, they usually die because of heat issues since they live so close to the engine and the ignition source.
On older style engines, that can accommodate the coil-over plug design coil packs, you will find sparkplug leads, these go from the coil packs to the sparkplug or on even older engines from the distributor to the sparkplugs.
If the sparkplug leads are brittle or damaged they can cause the spark to short to the nearest metal part, and usually, that is the engine, which also causes the fuel not to burn in the engine resulting in spluttering and jerkiness while accelerating.
7. Loose lug nuts
Loose lug nuts can be a silent killer, at first, you won’t feel it only up until the lug nut holes in the wheels are ovalized then you start feeling it and it gets worse the longer you drive.
It can get out of hand really quickly since when it starts vibrating it is close to breaking away from the vehicle.
So if your vehicle just starts vibrating out of the blue while accelerating pull over in a safe spot and inspect your lug nuts.
8. Death wobble
If you are a big Jeep Wrangler fan you will know these two words by heart, it isn’t just limited to Jeep Wranglers but can happen to any front solid axle vehicle (usually big heavy offroad orientated vehicles).
If a front solid axle vehicle has no or no good stabilizer shocks on the steering and you drive over a bump or pothole both front wheels will oscillate left to rate at a rapid rate, resulting in a violent shaking experience and the only way to make it stop is to come to a dead stop and pull away again.
9. Stuck brakes
This vibration works the other way around than most of the other problems, it is at its worse at slower speeds and gets better as you speed up, but beware of the sound that comes with it.
The brakes typically get stuck on vehicles that stood still for a long time in a damp environment.
What usually happens is the caliper piston, that pushes the pad onto the disc, gets a layer of rust on the sleeve of the piston and when you apply the brakes the first time after the vehicle has been standing can get stuck moving out of the caliper sleeve or moving back in.
The sound of a brake that is stuck is horrible and the smell isn’t pleasant as well, there is also a risk of it catching fire to top it off due to the friction.
10. Dirty or broken MAF
Let’s first get to know what a MAF is, it is an abbreviation of a Mass Air Flow sensor.
This is how the engine ECU can figure out how much air is entering the engine and the temperature of the air so it can adjust how much fuel is needed for the certain situation it is in at the moment.
If the MAF is dirty or broken the engine will have hesitations (jerkiness) under acceleration and you will also experience really bad fuel mileage as well.
The MAF has a bigger chance of getting dirty than failing, and you can easily remove it and clean it with an electronic contact cleaner.
11. Electronic throttle problems
This is a modern vehicle problem, since most vehicles, these days use E-throttles or electronic throttles.
The throttle pedal on the inside of the vehicle isn’t connected directly to the engine’s throttle body.
The pedal has a potentiometer inside of it to pick up how much you are pressing on the pedal and transfer that info to the throttle body on the car.
These potentiometers can get dirty inside and skip certain levels of throttle inputs and cause the car the hesitate and jerk around when accelerating.
12. Clutch or Flex plate is loose
This is something to look out for after there was work done on your transmission, clutch, or torque converter.
If the flywheel or flex plate(the flywheel for an automatic car where the torque converter bolts to) aren’t secured properly to the engine it can cause vibrations under acceleration but also just by idling.
It is something you need to address as quickly as possible because it can become a flying machine of death, it will saw through the floorboard of a vehicle and anything in its way if it breaks loose.
Final thought on cars shaking when accelerating
Hopefully, this article will help you determine what is causing your vehicle to shake when accelerating.
Some reasons are very similar to when a car shakes when braking.
While most of the problems mentioned here are easily identifiable there are some that are tricky if you haven’t messed around with cars a lot.
If you struggle to figure out what is the cause take your vehicle to a trusted workshop and have a professional have a look.