Idle at 250 rpm

My car idles somewhere around 250 rpm and I can't seem to find a fix for it. besides how low it idles, there isn't anything noticeable about it. The RPMs don't dip or jump suddenly, is just constantly sits at 250. Also I feel like the car lacks some power. I have to push the gas down hard to get the car to move at a reasonable pace.

My car has 86000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Most engines would not be able to stay running if the RPM’s are at 250 RPM’s. You may have another problem that is causing the gauge to not read correctly. If the vehicle brake is held while you push the accelerator, the computer will limit the throttle opening speed and may even limit the throttle opening maximum. You will need to have the computer scanned and the brake switch checked for proper adjustment and operation. You may also need to have the throttle plates cleaned of carbon. If you want to have a certified technician take a look at your car firsthand, a professional from YourMechanic can come to your home or office to test the vehicle and diagnose your car’s loss of power issue.

How to Identify and Fix Common car Problems ?

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to idle between 700 and 750 RPM.
Typically, the idle speed will be set at a value in the range of 600 to 800 RPM, but the exact value will depend on the number of engine cylinders and whether the vehicle is equipped with a manual or automatic transmission.
The throttle body for the Nissan Altima is known for carbon buildup, and requires regular, light cleaning to maintain peak performance. After cleaning the throttle body, many owners notice a very high idle, erratic (bouncing) idle, and unpredictable power surging.
Engine hunting and surging at idle is usually caused by a fuel delivery, air leak, or governor system problem. Cleaning/overhauling the carburettor, adjustment of the governor, and/or changing the air filer may be required.
The idle speed should feel consistent without skipping or slipping. In most of today`s cars, an idle speed of 600 to 1000 RPMs is average. If your car is idling rough, though, it won`t feel smooth. The RPMs will jump up and down, for example, or they`ll fall below 600 RPM (or whatever is typical for your vehicle).
Typically, engines idle at about 600-800 rpm. Older engines may go up to 1200 rpm or more while warming up. But if the engine is revving up while idling, even after it`s sufficiently warmed up, you might have a problem. High idle speeds waste fuel, cause extra wear and tear on your engine, and can be unsafe as well.
Other possible causes of a high idle include vacuum leaks, EGR system malfunctions, malfunctioning oxygen sensors, dirty fuel injectors, fuel pump malfunction, faulty spark plugs, a faulty mass airflow sensor, a malfunctioning throttle and, rarely, a PCM/ECM malfunction.
Normal idle speed for your vehicle, once the engine is warm, should be around 750 RPM (roughly). Two thousand RPM is significantly out of range high, even for a cold engine. The occurrence of this high idle speed might be a coincidence and thus not related to the alternator repair.
A clogged engine air filter or dirty throttle body may not allow the proper amount of air to flow while the engine is idling and cause a low, rough idle.
Replace the sensor with a compatible one and correctly install the crankshaft position sensor to ensure that the engine runs optimally and safely. A qualified technician can prevent further issues with RPM fluctuations while driving by installing the sensor correctly.
The engine`s oxygen sensor will detect the extra oxygen entering the engine via the vacuum leak which will alert the engine`s computer that the exhaust is running lean, which will prompt the computer to pump in additional fuel, resulting in an abnormally high idle.
However, when the engine RPM drops below the normal range of 800 RPM (for most cars), it is more than likely that you are dealing with an IAC valve problem. In cases where this valve is clogged or is failing, your vehicle will stall instead of slowing to an idle after the release of the throttle.
How many RPMs should a car be at 70 mph? In general, it is best to stay between 2500-3000 RPM when driving a car at 70 mph.
Here are some standard ranges for RPMs based on your car`s driving status: Idle: 600 to 1000 RPM. Accelerating: 2,000 to 2,500.
500rpm is a bit low to me . Most cars I`ve dealt with it`s around 850rpm . If the idle is set to low when you come to a stop from running at a faster speed ( especially quick ones ) the idle speed may not be high enough to compensate to keep the engine running .
Avoid revving your accelerator to a high revolutions per minute (RPM). It`s better for fuel economy, as your engine uses less fuel when it is revolving slower, at a lower RPM.
Running at lower RPMs equates to higher torque and thus lower horsepower, while making higher RPM power outputs less torque and higher top horsepower. In a straight line race, higher RPMs take precedence.
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.
Shifting between 2000 and 3000 is normal.
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.
Most cars should idle between 600 RPM and 1,000 RPM. Cars that idle below 600 RPM or above 1,000 RPM may have a mechanical issue that you need to address. Additionally, if the RPM jumps around when idling, this also may be a sign of a bigger problem.
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 reasons a Nissan Altima has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
Normal idle speed for your vehicle, once the engine is warm, should be around 750 RPM (roughly). Two thousand RPM is significantly out of range high, even for a cold engine. The occurrence of this high idle speed might be a coincidence and thus not related to the alternator repair.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Idles between 500rpm and 1300 rpm. Main concern is low rpm. Belt or pulley chirping mainly at low rpm Drives perfect but Idles bad
ANSWER : Hello. From what you describe it would appear that your vehicle may have more than one issue.

Belt chirping is usually caused by a worn belt or tensioner. If either component wears out the belt may loosen and chirp when the engine is started, or cold.

The low rpm low quality idle can be caused by a few different things. I would look at the idle air control valve, as that is the component that maintains the vehicle idle, and at any vacuum hoses that may be cracked or damaged, and possibly leaking. This is more likely for older or high mileage vehicles.

If you’re unable to pinpoint the issue yourself, consider YourMechanic, as one of our mobile technicians will be able to come to your home or office to diagnose your starting issue firsthand and make the necessary repair to your car.

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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.

Read Full Q/A … : Idle at 250 rpm

1992 Plymouth Grand Caravan 3.3 V-6 Heavy off idle miss. Smooths out at higher rpm.
ANSWER : Hi there. To be honest, you lost us at swapped ECU twice with junkyard units. The problem with replacing OEM ECU and not having them correctly programmed by the dealership is that any realistic chance of diagnosing a misfire issue as you’ve indicated pretty much goes away. I wish we could help, but without a proper reprogram, there really isn’t much we can offer.

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After driving awhile, when idling, RPM drops below 500 & car stalls. Happens rarely but RPM fluctuates, and drops suddenly.
ANSWER : If you are having a stalling problem then you may have a computer code stored in memory. I suggest having the computer scanned to see if there is any codes stored and diagnose them as needed. The intake hose and air filter should be inspected for leaks in the hoses and dirty or leaking air filters. If the air filter is dirty or leaking then have the mass air sensor cleaned. If you still need help, have a mechanic diagnose the stalling issue for you and let you know exactly what repairs should be done.

Read Full Q/A … : Idle at 250 rpm

After replacing the power steering pump there was a low idle, idle screw is all out, running rich, and idle speed doesn’t change.
ANSWER : Hi there. The engine has a vacuum leak and is causing the engine to stumble down on the idle. Check all of the vacuum hoses and the brake booster for any leaks. The engine is rich for it’s not burning all of the fuel properly and may also have bad spark plugs. If you need further assistance with engine not adjusting the idle, then seek out a professional, such as one from Your Mechanic, to help you.

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Frequent RPM shift with AC on on Idle
ANSWER : I would check to see if the software in the ECM is the latest available. If not, flash update the ECM. The fluctuation is a direct consequence of the control strategy programmed into the ECM as well as any other body controls modules that have microprocessors controlling HVAC. If the high frequency excursion in the idle is not due to faulty sensors, feedbacks, and so forth, that means that it is a programming issue. If you can get high enough within the Ford organizatoin, or somehow obtain the services of an ECM specialist, they can get to the root cause and resolve it via reprogramming of the control strategy. I do tend to agree with you that this is a potential vehicle defect but to resolve it you will have deal directly with Ford and/or an automotive engineering/design specialist who can possibility get in the ECM and modify the control strategy. As far as the effect on vehicle fuel efficiency, such is nil based on the particulars (idle variation of 200 RPM) you have described. The negative effect, if any exists at all, will be too small to measure. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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Engine rattling at high rpm, P0180 code stored, unsteady rpm at idle, no vacuum leak, mail carrier vehicle, please help!
ANSWER : Hi there. The reason why the mechanic told you that the source of your problem was a fuel temperature sensor is due to the error code you listed. P0180 is a generic OBD-II code that is triggered by a malfunctioning fuel temperature sensor ’A.’ This could indicate that the sensor is not within specification, or that the fuel temperature or fuel rail is too hot or too cold. The temperature of the fuel rail can be increased or decreased by a vacuum leak, faulty mass air flow sensor, EGR valve or O2 sensors that are damaged. In some cases, the trouble codes are not the best way to diagnose a problem. As such, I would recommend having a professional mobile mechanic come to your location to diagnose the symptoms you’re having by completing an engine idle is rough inspection.

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Car had a hunting idle so replaced Iac valve and now it idles at 2200 rpm’s cold and 1000 rpm’s warmed up.
ANSWER : Hello. You car does have an adaptive memory when it comes to the idle control valve. Over time the computer is going to adjust the placement of the valve to compensate for water and carbon build up. In some cases, driving the vehicle around 100 miles straight will cause changes. But more importantly, going through 20 or more key cycles will cause the idle control valve to adapt.

The best way to resolve this would be to use a factory scan tool that will allow you to go into the computer and clear this adaptive memory back to factory. If you are looking to have this done, consider using YourMechanic, as a certified mechanic can come to your home or office to inspect and repair your high engine idle speed problem.

Read Full Q/A … : Idle at 250 rpm