Car vibrates and tachometer indicator goes up and down

I noticed my car vibrates gently when it is not in motion. Whenever it starts to vibrate the tachometer indicator moves up and down usually between 0-1. The vibration is now more frequent. What could be wrong.

Thank you

Karen

My car has 54400 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Idle fluctuation can be caused by a number of things. A vacuum leak can be one cause. If there is a broken or disconnect vacuum line, broken air intake hose, or gasket leak, the engine can draw in too much air. This effects the air/fuel mixture and can cause a surging idle or even stalling. Low fuel pressure can also be a cause. Either a weak fuel pump or fuel pressure regulator, or even a clogged fuel filter can cause this. Other causes can be one of the numerous sensors the engine control unit relies on for information. If for example, the coolant temperature sensor is not giving the ecu correct information on engine temperature, this can effect the air/fuel mixture and cause an erratic idle.
Since any of these components can cause a poor idle, have a certified technician look into the causes to find the exact one.

How to Identify and Fix Common car Problems ?

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

Your tachometer needle will bounce up and down if your engine has a vacuum leak. The vacuum created in the combustion chamber is used as a power source, and, as such, it is routed through the engine to various locations using vacuum hoses.
There are two things that will cause your tachometer needle to move erratically. The first one is a vacuum leak in the engine. The second is a problem with your vehicle`s fuel injectors.
Shaking or vibration may be caused by many different 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.
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.
Tachometers and Speed Transmitters require a permanently mounted speed sensors that observe a target on the machines rotating shaft. Several types of sensors are available including Proximity, Hall Effect (magnetic), Optical and Laser. Permanently mounted systems usually use a Proximity or Hall Effect type sensor.
If vibration is felt at certain speeds, the tires may need to be balanced. If the tires are wearing unevenly and causing the car to vibrate, the driver may need a tire rotation. In some cases, the driver may need new tires to solve the problem of vibration.
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.
The tachometer is located on your instrument panel, and tells you how fast your engine is moving, in terms of revolutions per minute (RPM). The tachometer is a semicircle, with a hand that points to a number.
Tachometers operate by reading a signal from your ignition system. This is a “pulsed” signal. Each pulse is counted and the microprocessor converts this frequency into the pointer movement you see on the dial. Gasoline engines generally count the number of times the coil fires.
The most common reasons for your car to excessively vibrate are a problem with your tyres, wheels, brakes, steering, suspension, axle or engine.
Your motor mounts attach your engine to your car`s frame and if they are broken, they will cause your vehicle to shake at a red light. Your transmission also has mounts that secure it to the engine, and these, too, can cause unwanted vehicle vibration. You can isolate this issue yourself.
Strong spark plugs help in quick engine ignition and can help in maintaining your RPM levels optimal. When your spark plugs become faulty, your engine needs to work more due to low combustion. Poor combustion makes your RPMs high and makes you slow down on acceleration.
The most common signs of bad spark plugs include start-up trouble, rough idling, sluggish acceleration, declining fuel economy, engine misfiring, and engine knocking.
Uneven idling and vibrations is a major warning sign that indicates faulty spark plugs. The car engine will run at lower RPM during idling and runs smoothly without any noticeable vibrations or sound. Failing spark plugs can result in the engine to become rougher and produce vibrations when left at idle speeds.
Any unusual shaking or vibrating forces coming from the engine is cause for concern. It could be something as simple as old spark plugs producing an uneven power delivery, it could be something serious like worn or broken engine mounts, or it could be even more serious in the case of internal engine damage.
Monitor whether the needle seems to be moving erratically.

If you`re moving at a steady speed, the needle shouldn`t be jumping around (or the digital display shouldn`t be changing rapidly). If it is, it`s a sign the tachometer is bad.

When the torque converter starts malfunctioning, you may feel shuddering and even slipping in overdrive. You usually notice your car shuddering because it feels like it`s vibrating. Your car will vibrate even when you`re not going very fast. The shuddering makes the car lag and is very noticeable.
As you accelerate, your car`s engine is receiving a much higher dose of fuel than when at idle and conversely, when you let off the gas pedal, there is a sudden change in this fuel supply as a result of your foot letting off the pedal.
If your RPM goes up when you are slowing down or braking, don`t worry, this is totally normal. When you brake, your car is slowing down to a stop. Your car`s automatic transmission is trying to adjust for the change in speed and this adjustment can cause your RPM to go up.
When the engine is cold, the engine does not run as well, so it counteracts this by running at higher RPM to avoid stalling. The main issue is fuel vaporization. Fuel vaporizes at 196*F (91*c).
If your RPM goes up when you are slowing down or braking, don`t worry, this is totally normal. When you brake, your car is slowing down to a stop. Your car`s automatic transmission is trying to adjust for the change in speed and this adjustment can cause your RPM to go up.
When the engine is cold, the engine does not run as well, so it counteracts this by running at higher RPM to avoid stalling. The main issue is fuel vaporization. Fuel vaporizes at 196*F (91*c).
When the engine is cold, the engine does not run as well, so it counteracts this by running at higher RPM to avoid stalling. The main issue is fuel vaporization. Fuel vaporizes at 196*F (91*c).

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Car not speeding up smoothly, service engine light on when first start driving and car vibrating
ANSWER : Hi There,
It sounds like you may have a dirty or faulty mass air flow sensor. The problem this can cause may also be compounded when the engine is cold due to the change in air density in cooler weather. The mass air flow sensor monitors air intake as it is mixed with fuel prior to being injected into the motor. This sensor relays information about fuel and air temperature, air speed entering the motor and many other things to the ECM which uses this to make adjustments to fuel supply to the motor. A dirty or faulty sensor can cause an imbalanced air/fuel load to be supplied to the motor which results in an over fueling or under fueling situation depending on the conditions. This type of inconsistent fuel supply to the motor may cause a hesitation, loss of power, a jerking reaction, potentially a bit of black exhaust smoke and typically a strong smell of fuel when this sensor is malfunctioning. I would suggest having a professional from Your Mechanic come to your home to diagnose and inspect your vehicle.

Car vibrates and tachometer indicator goes up and down
ANSWER : Idle fluctuation can be caused by a number of things. A vacuum leak can be one cause. If there is a broken or disconnect vacuum line, broken air intake hose, or gasket leak, the engine can draw in too much air. This effects the air/fuel mixture and can cause a surging idle or even stalling. Low fuel pressure can also be a cause. Either a weak fuel pump or fuel pressure regulator, or even a clogged fuel filter can cause this. Other causes can be one of the numerous sensors the engine control unit relies on for information. If for example, the coolant temperature sensor is not giving the ecu correct information on engine temperature, this can effect the air/fuel mixture and cause an erratic idle.
Since any of these components can cause a poor idle, have a certified technician look into the causes to find the exact one.

My car vibrates when I’m waiting at the light . It drives fine . And it vibrates more when I turn on the ac? Can itvtve motor moun
ANSWER : There are two principal possibilities: faulty motor/transaxle mounts, or an engine operating or mechanical condition including the possibility of a faulty harmonic balancer. To obtain a conclusive diagnostic, please simply request an engine vibration diagnostic and a certified Mechanic, dispatched by YourMechanic right to your location, will get this resolved. If you do need new motor/transaxle mounts, genuine OEM Nissan mounts are recommended in order to maximize the chances of resolving the problem. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

When stopped in Drive, the car vibrates. You can especially hear and feel the vibration mostly in the back of the car 2002 Infiniti I35
ANSWER : Hello – I would be suspicious of an exhaust system hanger which has gone weak, and is allowing the exhaust to bump into the chassis at an idle. It is also possible that the fuel pump is wearing out, and the "chattering" that a worn fuel pump makes is transmitted through the fuel tank into the car. It would be easier to notice at a stoplight, but fades while driving as other road noise increases. I recommend a vibration and noise inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

I put the wrong key in my car and a few weeks later my car just shut down and it will not start I believe it’s the computer but…
ANSWER : Hi there. What had happened is the wrong key set the security to the vehicle. This is to prevent the vehicle from starting with the wrong keys. Try removing the battery cables (+) and (-) for 13 minutes. During that time, put the original key in the ignition and turn it on. Activate everything in the car even though there is no power. Then remove the key and hook up the battery cables. The computer should have reset and reset the security. If the security is still being tripped, then I recommend seeking out a professional, such as one from Your Mechanic, to help you

After unlocking the car from the drivers side, if the passenger door is opened before the key is put in the car the alarm goes off.
ANSWER : The key should only unlock the driver door with one turn and unlock all of the doors with two turns. If the passenger door is unlocking when the driver door is turned with one turn or if the alarm is still set if the driver door is turned two times, then the Immobilizer System Module needs replaced if you are intending on not using a key fob or you will need to get a key fob to manually turn off the Immobilizer System Module. If you need further assistance with your doors unlocking unusual, then seek out a professional, such as one from Your Mechanic, to help you.

My car started idleing rough, vibrations soon as start car, vibrations soon as I accelerate, vibrations, rough idle bad
ANSWER : This sound like you may be having an engine misfire. Have the system checked and scanned to see if codes are present for an engine misfire. If it is, then a mechanic can check to see if a coil or spark plug has failed. You may have oil leaks in the valve cover seals that has caused the ignition to short out in the spark plug holes. A repair of your valve cover gaskets may be necessary, along with the other components that I’ve mentioned. I’d recommend having the vehicle looked at by a qualified technician who will be able to diagnose these misfiring symptoms and fix it accordingly.

Oil leaking from under car and "remote control car" sound when car is first started for a few minutes until it warm up.
ANSWER : Hello,
There are a number of things that could make an engine noisy when starting up. Depending on the specific type of sound you are referring to, this will determine how to properly diagnose. If there is a bit of a hissing sound, this may be a sign of a vacuum leak. If this is more of a shrieking sound, this may be a sign of a worn out or out of adjustment serpentine belt. If there is a bit of a howling or growling sound, this may be a sign of a worn out or low on fluid power steering pump. A rattling or pinging sound may be caused by an ignition problem. An engine can ping (or knock) due to an improper combustion process. A "spark knock" is the result of combustion occurring too early. Early combustion can occur from carbon buildup inside the combustion chamber, a lean air/fuel mixture, and advanced ignition timing (spark plug firing too soon). A clattering type sound may be a result of improper lubrication in the valve train which could be a more serious problem and should be addressed as soon as possible. I would suggest having an expert from YourMechanic come to your location to diagnose and inspect your vehicle to ensure everything is in proper working order.