Reduced speed and hesitation

while driving speed reduces to 30 miles
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hello,
There are a number of things that may cause the car to hesitate when accelerating such as low fuel pressure, a dirty or faulty mass air flow sensor, clogged or dirty fuel injectors, a faulty throttle position sensor or potentially a bad fuel pump. Additionally, this may be caused by an internal fault detected in the transmission causing the computer to put the car into a "safe mode" or limp mode to prevent further damage. I would recommend having a professional 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 hesitation while accelerating can be the result of a number of issues, including something like a clogged fuel filter or even a broken fuel pump. Sometimes, something could also be wrong with the transmission.
If your car hesitates when you try to speed up at a low speed, it`s likely because the air and fuel ratio is too lean. A lean air-to-fuel ratio means the gas going into your engine doesn`t have the right amount of fuel and air.
When you press down the accelerator pedal and get minimal output, it could mean you have a problem with your fuel system. The most probable issue is a clogged fuel filter. Your fuel filter works to ensure that dirt and debris do not get into the fuel system.
Wondering why your car feels sluggish when accelerating? It could be due to a dirty air filter, a bad spark plug, or a faulty catalytic converter — among several potential suspects behind sluggish acceleration.
One of the most common reasons for poor acceleration is a problem with your car`s air intake system. If there is something blocking the air flow into your engine, it will prevent your car from getting the oxygen it needs to create the combustion needed for acceleration.
Clean or replace your vehicle`s air filter when your acceleration is acting sluggish. Put in new spark plugs when they go bad if your engine misfires and hesitates. Replace your vehicle`s fuel filter when there`s a delayed response when you accelerate.
Rough starts, hesitation and poor acceleration are all common symptoms of a bad spark plug. If a spark plug or multiple spark plugs are faulty, they will have trouble creating the spark that causes the ignition process in your vehicle.
A common issue that leads to the engine RPM drop when upshifting is the clogging of the fuel pump filter. If cleaning the strainer didn`t help to eliminate the RPM drop, replace the fuel pump.
What could the problem be? There are a range of reasons why your car is juddering when you accelerate. Your vehicle could have dirty fuel injectors, a damaged fuel pump, a blocked catalytic converter, a faulty mass airflow sensor, broken spark plugs, or even an accumulation of moisture.
Culprits include a dirty fuel filter, clogged fuel tank strainer, clogged or failing fuel injectors, or a defective fuel pump. On most vehicles replacing the fuel filter is a DIY operation.
Irregular resistance within the fuel pump motor can lead to your car slowing down and being unable to accelerate. Failing to accelerate is a good sign that your vehicle`s fuel pump needs inspection.
The car can feel sluggish and heavy when there is a clogged air filter, a dirty fuel injector, or a problem with the oxygen sensor. A catalytic converter that is going bad can also make the car feel sluggish and heavy. The spark plugs may also be worn out or damaged, causing the car to lack power.
There are a few reasons why your car might be struggling to accelerate. It could be due to a problem with the timing belt, the spark plugs, or the fuel injectors. It could also be because you have a dirty air filter or a clogged fuel filter. The fuel system may also be low on fuel.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Problem with speed. No check engine light on but when accelerating speed, it decreases then speeds right back up. No stalling at all
ANSWER : Hi, thanks for writing in. This is a common problem associated with fuel/air delivery which is very commonly related to what is called a mass airflow sensor. This monitors the flow of air intake into the throttle body as it is mixed with fuel to deliver the right air/fuel mixture into the motor. When this is not working properly, this will cause this kind of hesitation or surging when trying to accelerate. I would recommend having an expert from YourMechanic come to your home or office to confirm a diagnosis on the issue and make or suggest the necessary repairs or replacements.

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When reducing speed and then trying to accelerate again car seems to struggle (rpm start going up) but the mph don’t
ANSWER : Hello. I would usually start by scanning the computer for codes. This would tell me if the computer is seeing anything out of the ordinary. If there are no codes, then I monitor the output of the sensors as the air flow meter can cause this. If everything is reading right, then it is likely a transmission issue. The CVT will act like this some of the time and work improperly other times. This is very common on this car. Changing the fluid will help some of the time, but not too often. If you need to have this scoped out, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose the loss of power and have this addressed appropriately.

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when driving speed slow down and resume to speed it begins to jerk i have to put in over drive to resume speed especially on hiway
ANSWER : You should have the vehicle scanned. The data from the speed sensor needs to be checked to see if the transmission or engine is the cause of the jerking. You may have a transmission solenoid that’s not shifting correctly, an engine misfire, or a sensor malfunction. Have a certified mechanic, like one from YourMechanic, scan and test your vehicle for you to properly diagnose the car’s jerking symptom.

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car is barely picking up speed from stationary position to 3rd gear
ANSWER : Hi there. Check the turbo on the engine. With the loss of power until the vehicle is driven normally after 100 meters and the lack of power going up steep hills, the turbo could have failed causing the engine to lose power. Remove the intake hose to the turbo and start the engine. Look to see if the turbo is spooling up or not. If its not spooling up, then the turbo shaft could be seized and would need replaced other wise the waste gate could be not functioning causing the turbo to stop boosting. I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose your loss of power.

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Car hesitates and jerks at low speeds
ANSWER : Hi there. There are some common issues that can cause this. I usually start by checking to see if the car needs a tune up. Worn out spark plugs can cause this. I usually also check the air filter and replace it if it is dirty. A dirty throttle body can also cause this. In some cases a diagnostic computer needs to be installed to see if the air flow sensor and fuel ratios are correct. A dirty air flow meter will also cause this. If you want to have this checked, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your car’s hesitation.

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Hyundai Elantra 2017- RPM is going up and same time Speed is reducing on Highway
ANSWER : In most cases this issue is caused by a faulty speed sensor on the transmission or a ECU glitch that should be reviewed or repaired by a Hyundai dealership. Since your car is a new model, it might be best for you to take your car to the dealership so they can determine if it’s a computer issue; which should be covered under warranty.

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reduce speed message
ANSWER : Hello, thank you for writing in. The vehicle will illuminate the reduced engine power warning light for many reasons. The throttle, a number of sensors, poor ignition, and many other factors can turn it on. If you have not driven the vehicle very far you may still be able to find the code that was set when the light turn on. These diagnostic troubleshooting codes are found when you run a scan on the vehicle. This can be done at most automotive parts stores and by a technician. Otherwise, with the vehicle running fine, you will likely not find a problem when inspecting the vehicle. The wait and see method might be best here. If it happens again, it wasn’t a hiccup and you know you need to take action. Try to scan the vehicle when the light is on.

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Low thunk when, at slow speed, the gas pedal is pressed. What could cause this? 2005 Jeep Grand Cherokee
ANSWER : Hi there – most likely, the "thunk" you describe is coming from a weak or failed motor mount. It is allowing the engine to move about when you apply the accelerator pedal, and the engine is hitting something in the engine compartment. I recommend an engine mount inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, confirm this diagnosis, and give you an accurate assessment of damage and cost estimate for repairs.

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