My car revs by itself when idle sometimes the car jerks a little what is the problem?
My car revs by itself when idle and sometimes it jumps one time it actually cut off also when it idle its over 1000 then goes down To around 500.
My car has 139000 miles.
Experienced mechanics share their insights in answering this question :
It sounds like you may have a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.
How to Identify and Fix Common car Problems ?
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This can be caused by a variety of things, including low transmission fluid levels, worn-out clutch pads, or a problem with the torque converter. Another possible cause of over revving is an issue with the engine itself. This could be something as simple as a dirty air filter or spark plugs that need to be replaced.
It could have a failing mass air flow sensor, a failing throttle position sensor, a problem with the fuel pressure, or even an internal transmission problem. It could also be one of countless other things.
Another feature with automatic vehicles is the speed sensor. This works to trigger the car to shift when a certain speed is reached. If this sensor is not working correctly, your car might not shift gears properly, which can make be the reason why your car revs up and down while driving.
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.
One of the most common causes of revving is a faulty ignition system. You can test to see if this is the issue by checking the spark plugs. If they`re dirty or covered in carbon, they might not be sparking properly, which could cause your engine to misfire and start revving.
Sudden unintended acceleration (SUA) occurs when a vehicle suddenly begins to accelerate in speed without a driver`s control. SUA happens when an electronic malfunction occurs inside of the vehicle, causing the throttle to expand and the vehicle to accelerate without the driver`s intervention.
If you hear your car engine stuttering, then the injectors may not be providing an adequate amount of fuel. To fix this, you should clean the injectors on a regular basis. Using a fuel injector cleaning solution might eliminate the issue of the car jerking.
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.
Along with faulty spark plugs, a build-up of dirt and grime is the likely cause of cars stuttering when idle. A clogged filter or fuel injection system can starve your engine of fuel or oxygen, causing your car to judder and shake.
Among the potential underlying causes are vacuum leaks, EGR system malfunctions, malfunctioning oxygen sensors, dirty fuel injectors, fuel pump malfunction, faulty spark plugs, a faulty mass airflow sensor, or a faulty throttle position sensor.
The most common cause of this revving is either a stuck throttle or the mass airflow (MAF) sensor. This fault should be addressed as soon as possible for normal operation as this revving can become dangerous if the vehicle is allowed to accelerate unintentionally.
Worn Out Spark Plugs
This means that your spark plugs are not igniting the fuel in each piston cylinder in a timely manner, causing your car to jerk around while accelerating. If your spark plugs are worn out they should just be replaced, as they are generally an easy and inexpensive repair.
Worn Out Spark Plugs
This means that your spark plugs are not igniting the fuel in each piston cylinder in a timely manner, causing your car to jerk around while accelerating. If your spark plugs are worn out they should just be replaced, as they are generally an easy and inexpensive repair.
Worn Out Spark Plugs
This means that your spark plugs are not igniting the fuel in each piston cylinder in a timely manner, causing your car to jerk around while accelerating. If your spark plugs are worn out they should just be replaced, as they are generally an easy and inexpensive repair.
A car that surges or jerks at high speed is potentially dangerous, especially in heavy traffic or in bad weather. If your vehicle jerks at high speed, you should stop driving it and have it inspected by a mechanic.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
My car revs by itself when idle sometimes the car jerks a little what is the problem?
ANSWER : It sounds like you may have a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.
When I drive it and come to a stop with my foot on the brake my car revs up and sometimes shuts off and I have to start up again 2006 Chevrolet Impala
ANSWER : Hi – first task is to read any problem codes, whether the Check Engine light is on or not. Most auto parts stores will do this for you for free on a "time-available" basis. Any codes extracted are useful for diagnostic purposes. Based on your symptoms, the throttle position sensor is a leading failure possibility. A malfunctioning idle air controller could also cause the unpredictable idling issues, but not a shut-off while driving. I recommend a car stalling 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.
Car revs high and jerks when first starting to drive car, while driving.
ANSWER : Hi There,
It sounds like you may have low transmission fluid or a faulty transmission control solenoid. As you know, automatic transmissions use pressurized hydraulic fluid to change gears. Every time a gear change is required, the car’s computer activates a transmission solenoid, which directs transmission fluid into the valve body to engage the correct gear. When this is faulty or not working properly, this can cause a delay in gear shifting or in some cases cause the car to not shift at all. This type of problem is amplified any time the transmission is low on fluid creating a drop in hydraulic pressure. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.
It sounds like you may have low transmission fluid or a faulty transmission control solenoid. As you know, automatic transmissions use pressurized hydraulic fluid to change gears. Every time a gear change is required, the car’s computer activates a transmission solenoid, which directs transmission fluid into the valve body to engage the correct gear. When this is faulty or not working properly, this can cause a delay in gear shifting or in some cases cause the car to not shift at all. This type of problem is amplified any time the transmission is low on fluid creating a drop in hydraulic pressure. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.
High idling, jumping while idling, idle air control valve code
ANSWER : Hi there. This can be caused by the issues that you mentioned or a number of other things. You need to make sure all of the connectors are making good contact. I would then need to know what codes are in the computer to know if this is a circuit issue or not. Most of the time, it is not the circuit but instead a vacuum leak.
If there is a vacuum leak, then the vehicle will act like this and the computer cannot control the idle. Most of the time it is a bad hose or an EGR valve that is stuck open. That is the most common cause for this. I typically remove the EGR to check it to feel the diaphragm on the bottom of it to see if it is moving correctly. If you need to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair your car’s idling issue.
My car jerks when I’m going 50-60mph and sometimes dies right after I start it up, when I’m in park or reverse.
ANSWER : Hi there:
On late 1990’s Nissan’s and Infinity models, there are sometimes issues with electrical relays that transmit electrical signals from the power source to individual components. I’m not sure if this is exactly what is going on with your Infinity, but your descriptions seem very worrisome to me. Before this problem gets worse, you should contact one of our local mechanics to complete an electrical inspection on your vehicle or a car is stalling inspection. This will allow them to pinpoint the source of your problems so that you don’t have to replace parts that are not damaged or the root source of your stalling issues.
My car is jerking while driving, and when sitting idle
ANSWER : You will want to have the fault codes in the transmission and engine computer read out. Based on previous transmission concerns, the operation of the CVT transmission is highly dependent on how well the engine is running.
Misfires, valves out of adjustment, all of these and other engine concerns can cause the transmission to behave poorly at times. You may want to enlist the help of a mechanic who will have the tools and expertise to determine the jerking issue you’re experiencing and make the appropriate fix.
When I’m driving, sometimes the car over revs and jerks when I shift gears after the cars been on for a while
ANSWER : Hi There,
What you are describing may be a result of a faulty speed sensor, potentially low transmission fluid or a even a faulty transmission control solenoid. As your vehicle travels down the road, the computer analyzes data being sent by vehicle speed sensors and engine speed sensors. Based on this information, the Engine Control Unit (ECU), or the Transmission Control Unit (TCM), executes the appropriate upshifts and downshifts by sending a signal to one of several shift solenoids. These transmission solenoids have spring-loaded plungers inside them, which are wrapped with wire. When this coil of wire receives an electrical charge from the TCM / ECU, it causes these plungers to open, allowing transmission fluid to flow into the valve body and pressurize the desired clutches and bands. When this happens, the transmission changes gears and you continue down the road. The computer controls the transmission solenoid in several ways. If the vehicle is equipped with a dedicated Transmission Control Unit, it can open or close the hydraulic circuit using a direct 12v signal. In some cases, the Engine Control Unit (ECU) can control the solenoid’s plunger by turning the ground circuit on and off. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your transmission.
What you are describing may be a result of a faulty speed sensor, potentially low transmission fluid or a even a faulty transmission control solenoid. As your vehicle travels down the road, the computer analyzes data being sent by vehicle speed sensors and engine speed sensors. Based on this information, the Engine Control Unit (ECU), or the Transmission Control Unit (TCM), executes the appropriate upshifts and downshifts by sending a signal to one of several shift solenoids. These transmission solenoids have spring-loaded plungers inside them, which are wrapped with wire. When this coil of wire receives an electrical charge from the TCM / ECU, it causes these plungers to open, allowing transmission fluid to flow into the valve body and pressurize the desired clutches and bands. When this happens, the transmission changes gears and you continue down the road. The computer controls the transmission solenoid in several ways. If the vehicle is equipped with a dedicated Transmission Control Unit, it can open or close the hydraulic circuit using a direct 12v signal. In some cases, the Engine Control Unit (ECU) can control the solenoid’s plunger by turning the ground circuit on and off. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your transmission.
My car is idling very rough.
ANSWER : The idle air control valve is common for causing a rough idle in many cars, but it sounds like you have already corrected that. Another thing you may also want to check is the crankshaft position sensor. A crankshaft position sensor monitors the position or rotational speed of the crankshaft. This information is used by engine management systems to control the fuel injection or the ignition system timing and other engine parameters. When this is faulty or not working properly, this will cause problems with the ignition system and generating spark transmission to the spark plugs resulting in starting problems, rough idling and other performance issues. You may also want to check the fuel pressure as low fuel pressure can also cause rough or poor idling if the fuel pattern being sprayed from the injectors is not consistent. This can also happen in the case of having dirty fuel injectors which may also interrupt the spray pattern of the injectors. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your car.
