Shaking

my engine is starting to shake and the engine light keeps flashing , I took it to the mechanic and said air is getting into it and said its a 400$ repair is this true or a rippoff

My car has 140000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi There,
Generally, the check engine light comes on when something fairly serious is going on with the vehicle. This can happen for many different reasons such as a faulty mass air flow sensor, a faulty O2 sensor, a bad catalytic converter, bad spark plugs or spark plug wires and many other reasons. Many of these types of issues may also cause the vehicle to shake or vibrate a bit as you describe. Due to the wide range of possibilities for the check engine light to come on, the best and most efficient way to narrow down the scope of what may be causing this is to have the vehicle hooked up to a scanning tool to download any potential fault codes that may have registered in the computer. This will allow a mechanic to determine more specifically what to look for in diagnosing your vehicle. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle to determine what may be causing your check engine light to come on.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

Common reasons for this to happen:

Loose connections at the positive and negative battery terminals. Very dirty or clogged air filters can also cause your engine to underperform. Loose timing belts are another likely cause. A mechanic will check these and replace them if they appear loose and worn.

The most common reasons a Ford Expedition shakes when braking are bad brake rotors, bad brake pads, or a bad wheel bearing. Search our network of RepairPal Certified shops near you to speak with a technician about your issue.
A rough idle is one symptom of a clogged fuel filter. Failing Electrical Components: A problem or failure in the ignition system or various electronic components can cause a rough idle. If this is the case, the problem will usually get worse as RPMs increase.
The most common reasons a Ford Expedition has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
Is it something you should get looked at? The short answer is, Yes! A shaking or rocking sensation from your truck`s engine compartment, plus engine misfires is an indication that a problem is brewing. It may be as simple as replacing your spark plugs, but it also may be more involved than that.
The most prevalent cause of vibration is problems with your wheels or tires. The potential problems include improper wheel and tire balance, uneven tire wear, separated tire tread, out of round tires, damaged wheels and even loose lug nuts.
Your vehicle could have dirty fuel injectors, a damaged fuel pump, a blocked catalytic converter, a faulty mass airflow sensor, broken spark plugs, or even an accumulation of moisture.
Some simple warning signs that the transmission is having problems: Transmission is slow to respond when shifting. Grinding, shaking, vibrating.
While it may seem like a small problem on its own, rough idling is a sign that some part of your engine isn`t working properly. Over time, rough idling can result in poor gas mileage, starting issues and major engine problems.
While some cases are less severe than others, a rough idle is usually identifiable by a shaking and bouncing sensation in the vehicle. You may also notice odd sounds, as well as inconsistent RPM counts. Normally, a vehicle should have a smooth and consistent RPM rate of around 1,000.
Oxygen (O2) sensor

An oxygen sensor monitors and analyzes the amount of oxygen in a vehicle`s exhaust system after combustion. A dirty, damaged or malfunctioning O2 sensor (or sensors) affects the air/fuel mixture, causing the engine to idle rough.

The most common cause of engine sputtering are issues with the fuel system. These can range from bad fuel filters, fuel pump issues, or fuel injector issues. The other possible source of the problem would be due to poor ignition – think spark plugs or ignition coil problems.
If you begin to feel persistent shaking in your car, it`s best that you get to the problem right away before continuing to drive. Continuing to drive with the shaking can result in further damaging parts, ruining your tires, and other costly problems that could be avoided by a quick trip to your mechanic.
Potential causes of a vehicle shaking at idle include a loose gas cap, loose battery cables, a worn throttle sensor, a damaged engine mount, or bad spark plugs. Perform a general inspection of your engine bay to look for damage. If you can`t repair the problem yourself, take the vehicle to a mechanic.
Shaking or vibration may be caused by things such as faulty spark plugs, poor fuel pressure or misfires. Other things such as a faulty idle air control valve may cause the engine idle to drop below the normal idling RPM which may also cause the motor to shake or vibrate more than normal.
Improperly functioning spark plugs cause an uneven burn of fuel in the engine, resulting in fluctuating RPMs and a louder noise. You might also experience increased vibrations of your vehicle while sitting idle or while traveling at low speeds. These vibrations originate from the engine and can shake the entire car.
The most common reason for a car to shake is related to tires. If the tires are out of balance then the steering wheel can shake. This shaking starts at around 50-55 miles per hour (mph). It gets worse around 60 mph but starts to get better at high speeds.
While idle, the engine will complete about 10 revolutions or more per second. Because of its vast speed, the gauge displays the counts as multiples of 1,000. A vehicle that is operating normally should measure at about 1,000.
The only fix is to completely replace the CV joint. The main purpose of motor mounts is to attach a car`s engine to the frame of the vehicle. A secondary purpose is to dampen or reduce engine vibration so the occupants of the car don`t feel the constant shaking or vibrating of the engine while it`s running.
The most likely cause of the shuddering most often happens in the vicinity of your car`s rims and tires. They plant your car to the road, and if anything is broken, will feel it. On a serious note, it may be a broken transmission mount or a broken caliper.
If your car shakes when accelerating, the source of the issue can range from imbalanced tires to worn-out spark plugs, loose lug nuts, and more. Most of these problems can be handled with a quick (but possibly pricey) trip to the mechanic.
The most common reason an F150 will shake is the wheels are out of alignment or you need to replace the joints. Especially if the shaking only occurs while driving. Other common issues include worn out motor mounts or faulty spark plugs.
Some simple warning signs that the transmission is having problems: Transmission is slow to respond when shifting. Grinding, shaking, vibrating.
Causes of a rough idle. Many different problems could result in a rough idle for your car or truck, including: dirty fuel injectors, clogged air filters, bad spark plugs, and a variety of exhaust system issues.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

My truck shakes at traffic lights
ANSWER : Hi. The symptoms you describe could be a dirty or malfunctioning idle air control valve. Especially when hot, when the engine gets a leaner mixture of air and fuel, the idle air control will have a greater effect on idle and low speed running. In general, it will not set a Check Engine code either. I would recommend having a rough idling diagnostic completed by a mobile professional mechanic, such as one from YourMechanic, to inspect the problem and replace the idle air control valve if needed.

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Truck running rough. Shaking while idling and seems to shake more when accelerating.
ANSWER : A faulty oxygen sensor can certainly cause an engine to run rough and cause a bit of shaking due to the imbalance in the air/fuel load. As you may know the [oxygen sensors]((https://www.yourmechanic.com/services/oxygen-sensor-replacement) which are part of your emissions system read exhaust gases to determine whether or not the appropriate amount of oxygen is present in the exhaust. Based upon this reading, this information is relayed to the car’s ECU which then makes a determination as to whether or not to add more or less fuel to the engine. When too much or too little oxygen is present, this will cause check engine light to come on. Too much oxygen may be present in the exhaust gas due to things like an exhaust leak, a vacuum leak, a faulty mass air flow sensor (causing a lean fuel condition) or faulty fuel injectors. Too little oxygen may be present in the exhaust gas may be caused by things like a clogged air filter, a failing mass air flow sensor (causing too much fuel to be introduced to the motor), bad fuel injectors or a clogged catalytic converter. When the O2 sensor is not working properly, this will cause false readings to be relayed to the computer causing inaccurate adjustments to be made to the intake and fuel system in your engine. You may also notice a very strong smell of fuel and poor fuel mileage. I would suggest having an expert from Your Mechanic come to your location to diagnose your truck’s running condition.

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My car is shaking – 2000 Ford Mustang
ANSWER : If the shaking is occurring with the car stationary, that would not involve the wheels or driveshaft, although it could implicate the torque converter. A shaking engine diagnostic would start with the motor mounts. If those are judged solid (there are tests), one should assess the mechanical condition of the engine by checking cylinder compression.

The reason for that is if cylinder compression varies too much, that variance alone can account for this symptom. If the cylinder compression is too low or varies too much from high reading cylinder to low reading cylinder, one would then try to rule out easily repairable items like a mispositioned timing belt or chain. Of course, if compression issues are traced to valve train problems, the heads have to be serviced.

Other potential causes of the vibration are a broken harmonic balancer, engine ignition timing being off, and flexplate and/or torque converter damage or imbalance. Prior to getting involved with diagnosing an imbalance in something as hidden as the torque converter, though, the engine should be put on a scope to determine if there is something going on in individual cylinder firing conditions that would account for the vibration. Varying power output from individual cylinders, due to possible fuel and ignition system problems, obviously will cause vibration: you could have a bad coil, plug, injector, and so forth. A scope makes that diagnostic easy.

I recommend having a certified mechanic, such as one from YourMechanic, come to your location to determine why the engine is shaking and suggest any necessary repairs.

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My car shakes and shakes even more when i turn on my AC
ANSWER : Shaking with the a/c on can be caused by a number of reasons. The a/c compressor puts a lot of strain on the engine because the compressor is similar to being a small engine itself. When the a/c is switched on, the engine control unit should trigger components such as the idle speed/air control motor, to increase the idle slightly to compensate for the extra drag of the compressor. If that does not happen, then the additional drag can cause a low,shaky idle and even cause the engine to stall. Stalling can happen more often with the a/c on and turning the steering wheel as the power steering pump also creates drag on the engine. Excessive shaking can also be attributed to weak/broken motor mounts as well.

Have a certified technician look into the engine shake to isolate the exact cause.

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2008 Dodge Caliber, The engine is shaking at idle on Drive and Reverse mode, but stops shaking when in Neutral and Park Mode. The
ANSWER : Hi there. There are a few things that can cause the engine to idle rough or shake at idle. The first would be that the engine or motor mounts are loose or wearing out. In this case, the engine will vibrate not only during idle, but acceleration as well. Other possible problems include ignition system timing problems or fuel delivery issues, caused by one of a dozen or more individual fuel or ignition system components. In order to accurately diagnose this problem, you should have a professional mobile mechanic come to your location and complete a car idle is rough inspection.

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When I start my car up it feels like it’s going to cut off it’s shakes the idle feels like it’s going to cut off it’s just shakes
ANSWER : Hello, thank you for writing in. There is a component on the vehicle known as the "idle air control valve", which is responsible for managing the idle speed when you are not on the throttle. It is also utilized when slowing down between letting off the gas and pressing the brake. If this valve is overly dirty, has an air leak, or has failed, you will experience similar issues. You may also need to look into the throttle itself, the intake air sensors, and the fuel pressure. Only further testing will tell exactly what system is having issues. For more help with diagnostics, contact our service department to schedule an appointment.

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Shaking while braking
ANSWER : Hello. I’ve had experience with new rotors being warped right out of the box. There is a limited warranty on the rotors from the store. If you can return them and get new front rotors or get them turned, that would be a good idea.

Hot spots normally don’t cause this problem in rotors, but it is more likely possible that there is a loose or worn wheel bearing in the front of the car. Also, loose or worn control arms, and worn-out lower ball joints can also cause this problem.

I would suggest you get your brakes and suspension inspected by a certified technician, such as one from YourMechanic.

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Shake when accelerating
ANSWER : Hi there:

Based on your input, there are a few items that you might want to have inspected by a professional mobile mechanic to determine what’s causing this shaking issue. First would be the tires and wheels for balance. Usually they will vibrate in the steering wheel progressively worse as you accelerate through the gears, typically starting to show up around 40 mph. Sometimes when you decelerate the vibration will slowly go away, but will still be there as you’ve indicated. Second, is possibly an issue with some front end suspension parts, including CV joints or tie rod ends. It’s highly unlikely that this issue is internal (meaning with the transmission or flywheel being out of balance), but that’s also something that a mechanic will keep in mind as they complete a car is vibrating or shaking inspection.

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