Driving your Kia Sorento with engine hesitation or slow acceleration is not only infuriating, it can also be dangerous when overtaking or when crossing an intersection. Sluggish acceleration is a symptom of an underlying problem with your Sorento, which must be resolved urgently before it does more damage to your vehicle.
The most common causes for slow acceleration in Kia Sorento are clogged air filter, dirty mass air flow sensor (MAF), clogged fuel filter, fuel pump malfunction, faulty oxygen sensor, dirty throttle body, worn spark plugs and clogged catalytic converter. Less common causes are faulty throttle position sensor (TPS), bad ignition coils, dirty fuel injectors, clogged engine oil filter, transmission problem, worn piston rings and blown head gasket.
1. Clogged air filter
If the air filter is dirty in your Kia Sorento, it can have a negative effect on the performance of the engine, as less air passes through the dirty filter which suffocates the engine. This ultimately also increases fuel consumption. In the worst case, the engine can stall if the air filter is extremely clogged.
Replacing the filter on your Sorento takes a few minutes and does not require any special knowledge. So this is the first thing you should check.
2. Dirty or faulty mass air flow sensor (MAF)
Defective or dirty mass air flow sensor (MAF) in your Kia Sorento can result in loss of power, uneven engine running, erratic idling, misfires, poor exhaust emission values including black smoke. The mass air flow sensor is part of the engine’s intake system and is located between the air filter box and the throttle valve. It is not only important for power delivery in your Sorento, but also for the lowest possible pollutant emissions.
What happens when MAF sensor malfunctions in Kia Sorento?
If the MAF sensor is defective or dirty, it does not send correct measured values to the control unit of Sorento. The optimal amount of fuel can no longer be calculated which results in either too little or too much fuel injected into the combustion chambers. The engine runs too “lean” or too “rich”. This can cause the engine warning light to illuminate in the instrument cluster and the fault can be read out by a diagnostic device.
What causes MAF sensor to fail in Sorento?
The mass air flow sensor is a wearing part. As the mileage increases on your Sorento, it can happen that increasingly inaccurate values are sent to the engine control unit. With a noticeable loss of performance and high mileage, a defective MAF sensor should definitely be considered. However, the sensor can also malfunction earlier. When driving fast in heavy rain, water can occasionally pass through the air filter, which can severely impair the function of the MAF sensor. In rare cases, the MAF sensor can also be damaged by oil vapors flowing back out of the crankcase ventilation after the engine has been switched off.
How to check if the MAF sensor is bad in Kia Sorento?
Reading out the fault codes using a diagnostic device is relatively reliable. If you see P0100, P0101, P0102, P0103 or P0104 code in the OBD2 scanner, it indicates a problem with the mass air flow sensor. However, it can happen that there are no error codes. In case of doubt, the sensor may have to be replaced. But this should only be done after an extensive analysis as the MAF sensor may not be responsible for the symptoms of poor acceleration in your Sorento.
Can I clean a dirty MAF sensor in Kia Sorento?
In some cases, cleaning the mass air flow sensor can help the sensor measure the correct values again. However, caution is advised here, as the sensor parts are very sensitive to touch. Find the location of the MAF sensor in your Sorento, unplug the electrical connectors, and remove the sensor from the housing. Spray at least 10 spurts of MAF cleaner onto the sensor and then let it air dry for an hour or until completely dry. Do not use cloth or cotton swabs to clean the sensor, as it can damage it.
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Note (MAP Sensor): If you can’t find MAF sensor in your vehicle, it is possible your vehicle may not have one, especially if its an older vehicle. Instead, the air mass flow rate is calculated by the control unit using the data from the MAP sensor. A faulty MAP sensor presents more or less the same symptoms as a faulty MAF sensor.
3. Clogged fuel filter
If the fuel filter is clogged in your Kia Sorento, not enough fuel can get into the engine. This causes loss of power and jerking of the vehicle when accelerating. In worse case scenario, engine cuts out while driving due to insufficient fuel supply.
If this happens, the control unit in Sorento can detect the lack of fuel problem and the engine check light will illuminate. You may see error code P0087 when you connect OBD2 scanner to your vehicle, which indicates a fault within the fuel delivery system.
How does the fuel filter get clogged in Sorento?
The fuel filter is designed to prevent rust particles and other debris from your vehicle’s fuel tank from getting into the engine, where they would cause expensive damage. If you don’t follow the maintenance schedule of your Sorento and don’t change the fuel filter on time, the permeability of the filter drops and so does the fuel pressure in the engine. To a certain extent it does not matter, but if the fuel filter becomes too dirty, the engine performance will be reduced.
4. Clogged catalytic converter
The catalytic converter is part of the exhaust system in Kia Sorento and its main purpose is to convert exhaust gases that are harmful to health and the environment into less harmful byproducts. Over time, toxins accumulate and clog up the catalytic converter, especially if the vehicle has racked up a lot of miles.
What are the signs of bad catalytic converter in Kia Sorento?
Common signs of clogged catalytic converter in Sorento are irregular running of the engine, unusual exhaust gas odor, poor fuel economy, engine check light illuminates, limited performance above a certain speed or loss of performance, and sometimes rattling noises.
How long does the catalytic converter last in Kia Sorento?
There are many factors that affect its service life, but typically the catalytic converter last between 70,000 and 100,000 miles in Sorento. However, it can fail much earlier due to other faults, for example: misfires in the engine, bad air-fuel mixture, faulty oxygen sensor or coolant in the combustion chambers can lead to catalytic converter failure.
5. Faulty oxygen sensor
The oxygen sensor in Kia Sorento monitors the level of pollutants in the engine’s exhaust gases and reports the data to the control unit that continuously adjusts the air to fuel ratio in the engine. If the oxygen sensor develops a fault, it will send incorrect readings to the control unit which can result in slow acceleration, loss of power, irregular idling, engine hesitation, or stalling.
Can a bad O2 sensor lead to catalytic converter failure in Kia Sorento?
Faulty oxygen sensors are the leading cause of catalytic converter failures. If you suspect a problem with O2 sensor, you should act immediately and get it checked by a professional mechanic. O2 sensors are relatively cheap compared to the price of catalytic converters, which can easily cost you over a thousand dollars to replace.
How to check for faulty oxygen sensor in Sorento?
If there is any fault in the oxygen sensor, it usually illuminates the engine check light in the instrument cluster of Sorento. You can diagnose the problem by connecting an OBD2 scanner to your vehicle. If you see any error code from P0130 to P0135 or from P0150 to P0155, it indicates a problem with the upstream oxygen sensor.
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6. Dirty throttle body
Dirty throttle body can also be the cause of slow acceleration in your Kia Sorento. The common signs of dirty throttle body are poor engine performance, erratic idle, the engine react poorly to movements of the accelerator pedal, and the engine sputters or stalls.
One of the main causes of a faulty throttle is internal contamination. The throttle valve regulates the supply of air to the internal combustion engine. Over time, dirt and grime that escapes through the air filter can accumulate in the throttle body, this results in improper throttle valve movement, which causes problems with the control of the air supply.
7. Faulty throttle position sensor (TPS)
The throttle position sensor or TPS is used to determine the opening angle of the throttle valve. The information obtained is sent to the control unit and contributes to the calculation of the amount of fuel required. The symptoms of defective throttle position sensor in Sorento are usually reduced engine performance, engine jerks, RPM fluctuations when idling and a slow drop in speed after the driver has released the accelerator.
If you see any error code from P0120 to P0124 on OBD2 scanner, it indicates a problem with the TPS sensor.
8. Fuel pump malfunction
The fuel pump in your Kia Sorento is like a beating heart that pumps fuel to the engine when the vehicle is running. A malfunctioning fuel pump can result in irregular or decreased acceleration, poor engine starting behavior, engine jerking or stalling while driving and a decrease in fuel efficiency.
Common causes of a defective fuel pump are leaks or contamination within the pump, this can illuminate the engine check light in your Sorento. Diagnostic codes that a bad fuel pump can trigger are P0230, P0231, P0232 and P0087.
9. Bad spark plugs or ignition coils
If the spark plugs in your Sorento are not generating sparks properly, the engine will no longer run optimally. This is often noticeable in a loss of performance and increased fuel consumption. You may also notice that the engine is not running smoothly or the engine is jerking while driving – sometimes the engine simply cuts out. If you continue to drive with a defective spark plug, you run the risk of very expensive consequential damage, for example catalytic converter failure.
The ignition coils are part of the ignition system on your Sorento and are responsible for amplifying the relatively low battery voltage from 12V to a high voltage of tens of thousands of volts for the spark plugs. A fault in an ignition coil can cause poor sparking which can result in poor engine performance. The symptoms of a bad ignition coil are more or less the same as a bad spark plug.
10. Dirty fuel injectors
Fuel injectors are part of the fuel delivery system that sprays fuel in the form of a high-pressure mist. Over time they can get clogged due to hydrocarbons, sediment and other elements in the fuel. When that happens, proper amount of fuel can no longer be delivered to the combustion chamber at the correct pressure.
Common symptoms of clogged fuel injectors in Kia Sorento are slow acceleration, rough idling, irregular engine performance, increased fuel consumption, engine hesitation and misfiring.
Is it safe to use fuel injector cleaners in Kia Sorento?
Cleaning the fuel injector nozzles using fuel additives almost always leads to an improvement in the injection behavior, since the additive dissolves the deposits on the nozzles. But before using your preferred injection system cleaner in your Sorento, it is recommended to find out if its approved by Kia in advance. Because the additive is poured into the fuel tank and gets through the entire fuel system and the engine. Some injector cleaners can cause damage to the oxygen sensor.
11. Clogged engine oil filter
The engine oil filter in your Kia Sorento ensure that the engine oil remains free of dirt particles, metal shavings, soot or unburned fuel, thus preventing damage. If the filter becomes clogged, it can cause the engine to sputter, the faster you drive, the more it sputters.
Although most oil filters have a bypass valve or pressure relief valve, which activates when the filter becomes clogged after it has not been replaced in time, but in rare cases the bypass valve can fail.
12. Transmission problem
A malfunction in the transmission can also be responsible for slow acceleration problem in your Sorento. Transmission is a complex component, it is responsible for transferring the power from the engine to the wheels. There are many gears that mesh with one another. Sooner or later this friction leads to wear on the components, especially if your Sorento has racked up a lot of miles or if you didn’t change transmission fluid in time.
A faulty transmission usually show other signs including grinding or clunking noises, jerky acceleration and burning smell.
13. Worn piston rings or valve seals
The piston rings are sealing element on pistons of the internal combustion engine in Kia Sorento. The purpose of both valve seals and piston rings is to keep engine oil out of the combustion chamber. When the piston rings are worn or damaged, the combustion chamber of the engine loses pressure. This results in reduced engine power as the piston is unable to fully compress the fuel and air mixture.
The most common symptoms of worn piston rings in Sorento are: blue colored smoke comes out of the tailpipe, a lack of acceleration power, excessive oil consumption and engine misfires.
14. Blown head gasket
The head gasket is responsible for providing the seal between the engine block and cylinder heads. Its purpose is to seal the combustion gases within the cylinders and to avoid coolant or engine oil leaking into the cylinders. Leaks in the head gasket can cause all sorts of problems including poor engine performance and/or overheating.
Common signs of leaking head gasket in Sorento are white smoke coming out of the tailpipe, coolant level going down as it burns in the engine, oil in coolant bottle, and milkshake color oil in engine due to mixing of oil and coolant.
How to check if head gasket is leaking in Sorento?
You don’t have to go to a workshop to check for a leaking head gasket in your Sorento. There are test kits available in the market in which you just have to insert a tube filled with colored liquid in the radiator (in place of the radiator cap), and then start the engine. If the liquid changes color, then there is a leak in head gasket.
Use OBD2 scanner for diagnosis
Since Kia Sorento is equipped with on-board diagnostics (OBD), a fault diagnosis can provide initial indications of where the malfunction is located.
To begin troubleshooting, you must first connect the diagnostic tool to your Sorento. The OBDII connector is usually located under the dashboard. With the tool connected, turn on the ignition. Most diagnostic devices then ask for some information about the vehicle. It is important that you enter this 100% correctly, otherwise the result of the search may be inaccurate. In addition to the vehicle make, model, and engine type, you usually also have to type in the Vehicle Identification Number (VIN). Since some OBD codes are manufacturer-specific, the scanner will be able to give you more accurate information if you enter more details about your Sorento.
Conclusion
There are many reasons why your Kia Sorento is not accelerating properly. When looking for the reason, you should always start with the most obvious causes, problem with air intake or fuel supply.
In any case, it is advisable for laypersons to visit a workshop. A professional mechanic can swiftly diagnose the sluggish acceleration issue for you.
While traveling out-of-state on 30 April and 1 May, on three separate occasions my 2017 KIA Sorento jerked and immediately lost power. On uphill grades I could not, even with the accelerator to the floor, could not get the vehicle above 30 mph. On level road I could accelerate to 60+ mph, but that acceleration was slow….again, even with the accelerator to the floor. However, I discovered that if I shut-off the engine, waited a minute or so and then restarted, acceleration was fully restored. On the downside, during the third incident, I was able to get the vehicle off the road but barely so before losing the power steering. On 2 May I took the vehicle to my local KIA dealership. As of this date, 4 May, the technicians have been unable to determine the cause of this problem….i.e., computer readouts do not show any error codes. So, the above article was helpful as it informs me as to what might have caused the jerking, deceleration and (at the third incident) loss of power steering. BUT, there is a disconnect between information in this article, how to diagnose and fix the problem and the fact that the problem with my Sorento cannot be identified and fixed. I assume tech manuals for the Sorento contain similar information. If those manuals do not explain what to do if computer testing does not indicate error codes, those manuals should include further instructions (i.e., visually inspect any element that might be the issue) for a technician to follow. This afternoon, I will return to the dealership and get my car. In all likelihood it will be returned to me without the problem having been addressed.
I think your fuel pump may be failing. It works fine most of the times and other times its acting up. Have you been driving your vehicle with less than half tank of fuel a lot? These vehicles use fuel to cool themselves. I have seen fuel pumps failing when driven with near empty fuel tank a lot.
Yes. I will replace my fuel
I have this deceleration issue with my Sorrento 2012 like yours when I drive up a slopy grade road. I thought it was my transmission slipping. Not really. When I shut the engine off for a few seconds and restart it the problem goes away. Next I will try replacing fuel filter and fuel pump. Jack.
My Kia Sorento 2006 CRDI is not responsive at the slight press of the pedal as it used to be , )this is after being overhauled and change Turbo), but RPM will go up easily past 2,000 rpm. Has anybody encountered this problem?
I’m having the same issue with my 2.5 crdi 2008 going up hill struggles looses power a lot so changing the mass air flow sensor next week see if that helps.
Sir, changing/replacing mass air flow sensor solve the problem? Cause I’m experiencing same issue.
Just read your article about poor acceleration on a Kia Sorento, I’m working on a 2011 that is giving me fits. I’m not a professional mechanic but am pretty experienced and knowledgeable but this one is frustrating. It’s my daughters car, a 2011 Kia Sorento with the 2.4L engine (non-GDI), automatic transmission AWD, it’s been acting up for awhile but got pretty bad recently.
The symptoms are poor/slow acceleration and a seeming lack of power especially on hills. When I drove it, it was also having trouble shifting, shifts okay the first couple of gears but has trouble shifting into higher gears, interestingly it shifts fine in manual mode. It had problems a couple of years ago with lack of power, ended up replacing the catalytic converter, even though it’s fairly new I did a back pressure test anyway (on the first/main cat converter) and it was fine, I guess it’s possible the 2nd cat is bad but looks like they replaced that one also.
Checked codes and only code was P2096-pending, 0 permanent codes. Checked compression and it was good, checked fuel pressure and it was good. Did some research online about reported symptoms that are similar and bad torque converter was one of the reported problems, also bad TPS sensor had similar symptoms but that wouldn’t cause shift problems, vehicle has almost 190k miles on it so I was leaning more towards bad torque converter.
I have seen online a number of reports about a software update on Kia’s for shifting problems, I checked and it had 4 outstanding recalls so took it to dealer and got the recalls done, one was for a shifter replacement. Still had same problems so obviously the dealer didn’t road test it after doing the recalls. Ended up pulling transmission, replaced torque converter and transmission wiring harness which is supposedly a known problem, got it all back together and took it for a test drive and same problem. Figured I’m this far into it and even though I’m not getting any codes, which I would expect, I went ahead and replaced the TPS sensor/throttle body, cleared the codes and took it for test drive, same problem, poor acceleration and seeming lack of power and still has problem shifting, even though this time I can get it to go into 3rd and sometimes 4th, like I said earlier it does shift in manual mode but not in automatic, scanned again for codes, none present.
Really frustrating, even more so that not getting any codes. I have purchased a new scanner that is more sophisticated and comprehensive but it has not been delivered yet. Any ideas ? If shift solenoids were bad wouldn’t that keep it from shifting whether in manual or auto mode ? Like I said, checked fuel pressure and it was good, that was at idle speed but my understanding of fuel pressure with fuel injection systems is the pressure is always the same regardless of throttle position, correct ? It’s got me baffled, any ideas or suggestions would be appreciated.