Why does my car slow down then speed up?

This may be a result of low transmission fluid or potentially a faulty transmission control module. A faulty transmission control module may cause a delay in acceleration or erratic shifting of gears.
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Why does my car suddenly slow down while driving?

The most likely issue is a clogged fuel filter. The purpose of the fuel filter is to ensure that dirt and debris stay out of the fuel system, so over time, it may need cleaned or replaced. When the fuel filter is clogged, the fuel pump has to work much harder, resulting in a far less efficient drive.
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Why does my car increase speed up on its own?

Sudden unintended acceleration occurs when an electronic malfunction within the vehicle causes the throttle to expand and the car to accelerate without the driver pressing down on the gas pedal. If a vehicle has a defect in its electronic system, the mechanism that controls the car's power train could malfunction.
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Why does my RPM go up and down while slowing down?

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.
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What does it mean when a car slows down?

A car that is slowing down is decreasing its speed. It is also accelerating, because its speed is changing. Imagine a car being driven down a road. If the speed is increasing, the car has positive acceleration.
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Car Losing Power | Loss of Acceleration | Finding the Fault With FIX



What are the signs your transmission is going out?

What Are the Transmission Failure Symptoms?
  • Refusal to Switch Gears. If your vehicle refuses or struggles to change gears, you are more than likely facing a problem with your transmission system. ...
  • Burning Smell. ...
  • Noises When in Neutral. ...
  • Slipping Gears. ...
  • Dragging Clutch. ...
  • Leaking Fluid. ...
  • Check Engine Light. ...
  • Grinding or Shaking.
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Why does my car feel like its losing power?

There are a lot of things that can cause your car to chug and lose power. Dirty, old, worn out, clogged filters are a common cause of car sputtering and losing power. A clogged or failing catalytic converter can cause all kinds of problems for the engine, including sputtering and stalling.
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What causes a car to surge while driving?

If an engine is not getting enough fuel (this is called “running lean”), due to fuel pressure (regulated by the fuel pump and regulator), restricted fuel injectors, a vacuum leak or really anything that throws off the fuel mixture going in to the engine, this can cause the surge.
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Why do my RPMs go up but car doesn't accelerate?

Recommended Services. Hello there, many faults will cause your RPMs to increase but the car not to accelerate. This is called a slipping clutch and happens when power is applied when in gear. There are several causes for a slipping clutch; the most common are a faulty clutch, pressure plate, or shift linkage.
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Why is my RPM gauge jumping?

There are a number of different issues that could be causing your RPM gauge to bounce or fluctuate while you're driving. Some of those include faulty spark plugs, a bad crankshaft sensor, or a bad idle air control valve.
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How do you fix a sudden unintended acceleration?

Ways of resolving sudden unintended acceleration are to apply the brakes and/or clutch, or shift into Neutral if the car has an automatic transmission. In most cars, fully applied brakes are easily capable of stopping the car while the accelerator pedal is also fully applied.
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Why wont my car accelerate when I press the gas?

Fuel and Air Delivery Problems

Poor acceleration can result from an engine that's running lean (not enough fuel). Similarly, a lack of airflow can also prevent the engine from accelerating as it should. Some of the most common causes of fuel and air delivery issues include: A weak fuel pump.
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How do I know if my fuel filter needs to be changed?

5 Signs that You Need to Replace Your Fuel Filter
  1. Car Has Difficulty Starting. This could be a sign that your filter is partially clogged and on its way to being completely dammed up.
  2. Car Won't Start. ...
  3. Shaky Idling. ...
  4. Struggle at Low Speeds. ...
  5. Car Dies While Driving.
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Can a bad fuel pump cause surging?

Irregular resistance inside the fuel pump motor may cause vehicle surging, and indicates a fuel pump in need of repair. Surging feels like the gas pedal has been used. However, it occurs at a random, consistent speed. If this happens often, it may be because of problems within the fuel pump.
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What does engine surge feel like?

Basically, when an engine surges, you notice your car speeding up and slowing down even while you keep the accelerator steady. You may notice the tachometer fluctuating, for example, from 1500 to 2000 rpm. At the same time, you may feel a soft and rhythmic jerking motion.
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How do I check if my fuel filter is clogged?

Signs Of A Clogged Fuel Filter
  1. Trouble Starting the Engine. The most common sign of a clogged fuel filter is trouble starting the car, since it depletes the oil supply going to the engine. ...
  2. Issues Accelerating. ...
  3. Frequent Idling and Sputtering. ...
  4. Strong Odors. ...
  5. Engine Misfires/Low Performance. ...
  6. When to Replace the Fuel Filter.
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What are the top 5 signs of transmission problems?

Top 5 Signs of Transmission Trouble
  • Grinding Noises. One of the more common symptoms of transmission trouble is a grinding noise that occurs during shifting. ...
  • Burning Odor. Transmission fluid often smells tart or slightly sweet. ...
  • Transmission Warning Light. ...
  • Delayed Shifting. ...
  • Transmission Fluid Leak.
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How do I know if my transmission fluid is low?

Symptoms of Low Transmission Fluid
  1. Drips or puddles underneath the car.
  2. Difficulty shifting through gears and/or slipping.
  3. Shuddering or shaking.
  4. Lurching or sudden jerks.
  5. Transmission won't engage.
  6. Humming or clunking noises.
  7. A burning smell.
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What does a slipping transmission feel like?

A slipping transmission tends to feel like your car is jerking or surging. You might even notice that the engine revs to a high RPM between gear changes. As you are driving, the transmission should be providing constant power to the wheels.
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Why doesn't my car accelerate like it used to?

If your vehicle speed changes without you accelerating or decelerating it, it could be low transmission fluid levels or a failing clutch. Problems with the ECU – The Electronic Control Unit, or ECU, is the brain of your car.
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Why does my car engine race when I accelerate?

Your vehicle could experience running too rich, meaning too much fuel or too lean, too much air.
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Why is my car revving high when accelerating?

Dirty Fuel Injectors Or Air Filter

As an effect, your car must reach a higher RPM to accelerate, causing the engine to rev while driving. The dirty fuel injectors can also cause a few other issues, such as the engine misfiring or a drop in gas mileage.
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Why is my RPM fluctuating?

RPM fluctuation is a common symptom of worn-out spark plugs, especially in older vehicles. Spark plugs that are worn out are unable to correctly fire the fuel within the piston at the appropriate time. This might result in sluggish acceleration. When accelerating, your automobile may experience misfires and jerking.
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