WHY DOES MY CAR SHAKE WHILE I'M IDLING?

When your car is shaking while idling, it usually indicates one of several problems. Some of these are relatively simple to fix, while others require more work or parts that can be expensive.

Engine misfire.
Engine misfire is a problem with the combustion process. It causes your car to shudder when you’re idling, rather than running smoothly. A vehicle with an engine misfire might also have trouble starting and lack power while driving. If you notice your car shaking while idling, there may be a problem with one of its spark plugs or faulty oxygen sensor that needs to be addressed by a mechanic right away.

Exhaust leak.
If you’re seeing smoke coming from the exhaust pipe when your car idles, that could be a sign of an exhaust leak. Check for leaks in the exhaust system (from hangers being loose or broken, for example) and make sure to look at how well connected everything is. Is there any rust on the bolts or nuts holding things together? Are they all tightened down as much as they should be?
If you notice a crack in one of your pipes, you may need to replace it entirely. If it’s just a small crack, try applying some duct tape over it to see if that does the trick—but don’t rely on this solution for too long because cracks can worsen over time and cause further damage!
And if there’s one thing we’ve learned from Seinfeld reruns: mufflers are important. A loose or broken muffler could lead to shaking issues when idling because it will affect how efficiently air flows through your engine compartment—and that means more friction and heat buildup inside your car’s engine bay!

Engine air filter.
The air filter is the second most common reason for a car to shake when idling. Most modern vehicles have a paper or foam filter that’s located somewhere in the engine compartment, usually behind a plastic cover. It serves two purposes: it keeps dirt from entering your engine and causing damage; and it keeps dirt from accumulating on your turbocharger or supercharger, which can reduce its efficiency and lead to overheating issues.
The best way to determine if this is your problem is by checking to make sure that you have an air filter at all! You’ll want to locate it under the hood of your vehicle, where there’s usually some sort of plastic shield protecting it from foreign objects like rocks or pieces of broken glass (or even other cars). If you see something like this without knowing exactly what it does or how often you should change it out—get in touch with us here at YourMechanic so we can help you out!

One or more faulty spark plugs.
The spark plug ignites the gasoline, which in turn creates power. If you have one or more faulty spark plugs, then it’s possible that you will have a rough idle and no acceleration while idling. It’s also possible that your car may not be able to start when it gets cold outside due to a lack of power from your engine.
One quick way you can check if this is the case is by checking whether all of your spark plugs are firing properly with an infrared tester tool. This is an inexpensive tool that can be found at most automotive stores and can help determine whether or not there’s a problem with the ignition system in your vehicle

Dirty MAF sensor.
The MAF (Mass Air Flow) sensor is a small device located in the engine bay that measures the amount of air entering your engine. This information is sent to the car’s computer, which can then determine how much fuel to inject and when to do so. If this sensor gets dirty or clogged, it may not provide accurate readings, which could cause problems with idle speed and fuel economy.
If you notice an issue with idling, one of the first things you should check is whether your MAF sensor needs cleaning or replacement. A few simple steps will help remove most carbon deposits from this part:
- Open up your hood and use a vacuum cleaner hose attachment to clean out any dirt or dust from inside the intake manifold
- Use aerosol carburetor cleaner on a toothbrush or cotton swab to scrub away any remaining buildup around the outside of your MAF sensor

Loose gas cap.
If your car shakes while idle, the first thing you should do is check the gas cap. The gas cap may not be properly sealing, it could be cracked or damaged, or it might just need to be replaced altogether.

Faulty oxygen sensor.
If your car shakes while idling, it may be that the oxygen sensor is faulty. The oxygen sensor is part of the exhaust system and monitors the amount of oxygen in the exhaust stream. It sends a signal to the computer that tells it how much fuel to inject into the engine. If it is faulty, it will cause a rough idle and poor acceleration

Throttle position sensor issue.
Throttle position sensors are designed to tell the computer how much throttle (gas) is being applied, so it can adjust its fuel mixture accordingly. When they go bad, you might notice a shaking when you’re idling. You might also see your Check Engine light come on and/or get an error code that indicates an issue with this sensor (for example P0128). If you suspect your throttle position sensor is bad, here’s how to replace it:
Your car may be telling you there’s a problem in the form of vibration. Along with a rough idle, you may experience a lack of power, no acceleration and a hard start when your engine won’t turn over. Check your gas cap and spark plugs first, but it’s best to go to a certified mechanic right away in case the problem is serious, which can lead to additional damage and higher repair costs if it’s ignored.
- Check your gas cap. If your gas cap is loose or damaged, it can cause the engine to run rough and shake while idling.
- Check your spark plugs. These are one of the most important parts of your car’s engine, so if they’re not working correctly, it could be a sign that something is wrong with other parts of the car too.
- Go to a certified mechanic as soon as possible! They’ll be able to diagnose any issues with your vehicle before they become more serious and costly to fix down the road. You can save money by doing some of this work yourself (like checking for worn belts) but it’s best to avoid trying anything complicated unless you’re confident in what you’re doing!
Conclusion
Be sure to check your gas cap and spark plugs first, but it’s best to go to a certified mechanic right away in case the problem is serious, which can lead to additional damage and higher repair costs if it’s ignored.