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- Symptoms Without Summary
- Car Leaking Coolant
- AC Isn't Cooling
- AC Blowing Hot Air
- Shaking While Driving
- Overheating AC
- AC Smells Like Vinegar
- Heater Not Working
- Windshield Wipers Don't Work
- Car Leaking Water
- Car Leaking Red Fluid
- Car Battery Leaking
- AC Only Work Sometimes
- Shaking While Idle
- Shaking At High Speeds
- Evap System Leak
- Shaking While Braking At High Speeds
- Shaking When Stopped
- Shaking When Accelerating
- Radiator Leaking
- Pink Fluid Leaking
- Car Leaking Oil
- AC Not Working.
- Car Leaking Gas
- Power Steering Fluid Leak
- Bad Brake Caliper
Hey, Why Is My Car's Engine Sputtering?
If you are short on time and want to fast-track the process to professional help, click Yes
Is Your Car's Engine Sputtering?
The engine is sputtering because of a faulty fuel pump or mechanical failure, causing the unmeasured fuel pressure to create sputters. But it can also be because of worn spark plugs, faulty sensors, or a damaged ignition coil.
While the unsettling feeling of your engine sputtering might not have to do with engine problems, it indicates something wrong with your car that you shouldn't ignore.
A sputtering engine relates to how your car intakes and burns fuel. If it doesn't burn fuel cleanly and efficiently, your fuel economy suffers, risking expensive repairs to your engine, exhaust system, and catalytic converter. Plus, your car creates excess emissions that damage the environment.
In addition, some issues related to engine sputtering can prevent your car from starting, leaving you stranded and in a dangerous predicament.
The good news is that engine sputtering is easy to recognize and more straightforward to identify when the "check engine" light comes on. If you take your car to a technician before the problem damages the engine, the fix could be as simple as replacing the spark plugs or cleaning the fuel pump. Unfortunately, putting the issue on hold can severely impact your car's fuel efficiency.
Let's Get To The Bottom Of It!
- You may also experience the check engine light flashing or vehicle hesitation during acceleration...read more
You may also experience the check engine light flashing or vehicle hesitation during acceleration.
If your fuel injectors are dirty or damaged, they lose their ability to effectively break down fuel and inject it into their corresponding engine cylinders. Properly atomized fuel burns completely, providing maximum power to the pistons and crankshaft that keep your engine spinning. A disruption to this process can cause the engine to chug and the "check engine" light to come on. In addition, the cylinders with dirty fuel injectors won't contribute as much power to the engine's crankshaft, which results in fluctuations in the engine's RPMs. These fluctuations are more evident while your vehicle is idling.
- You may also experience a rough idle or the check engine light on. Wear on your spark plugs direc...read more
You may also experience a rough idle or the check engine light on. Wear on your spark plugs directly affects your car's fuel economy.
The electrodes in a spark plug become corroded and separated from each other after years of use. While this micro-millimeter separation isn't apparent on the tiny electrodes, it often causes obvious tell-tale signs, such as decreased gas mileage, engine sputtering, and a sulphuric odor from the unburned fuel.
- You may also experience a rough engine at idle and notice the check engine light is on. A...read more
You may also experience a rough engine at idle and notice the check engine light is on.
A catalytic converter that functions correctly converts the emissions from fuel combustion into water vapor in your exhaust. The unconverted emissions will cause a noticeable smell if the catalytic fails.
- You may also experience a rough idle or the check engine light on. Your fuel pump could be failin...read more
You may also experience a rough idle or the check engine light on. Your fuel pump could be failing.
This pump inside the fuel tank is supposed to send fuel to your engine at the proper pressure and volume to get it started and keep it operating while your vehicle is running. The fuel pump keeps the pressure even when your car isn't running, so your engine is always ready to start. If it malfunctions, your engine might crank long before it starts. Listen for any extra noise. That delay before starting is the fuel pump building pressure once more.
- You may also experience a loss of fuel economy or vibrations and jerking while driving. T...read more
You may also experience a loss of fuel economy or vibrations and jerking while driving.
The engine control computer monitors your ignition coil to ensure it generates enough voltage to burn fuel thoroughly. Suppose a cylinder's coil isn't contributing to the process. In that case, the computer senses this and knows that significant quantities of unburned fuel go through the catalytic converter and into the exhaust. You can sometimes smell this wasted fuel and feel disruptions in the engine's running. This unburned fuel will damage the catalytic converter in short order. When an ignition coil fails to generate high voltage, the car's computer warns you by flashing the check engine light during this ignition misfire.
- You may also experience a loss of fuel economy or vibrations and jerking while driving. Y...read more
You may also experience a loss of fuel economy or vibrations and jerking while driving.
Your engine needs both fuel and air to burn it to generate power. That's where the mass airflow sensor comes in. This sensor measures the air coming into the engine to calculate the proper amount of fuel to inject to maximize the vehicle's fuel economy. If the sensor wires on this instrument get dirty, it will no longer give accurate readings, and the fuel-to-air ratio in the engine will be unbalanced. If the vehicle's computer senses an odd amount of air compared to the space in the throttle, the check engine light will activate, and the engine won't run as smoothly as it should.
Find Professional Help
Please select your vehicle's brand and location so we can locate the best professional help for youVehicle Health Inspection Proof
Explore the following typical inspection results that show a potential cause for the symptom and select the one you believe is similar to your vehicle's issue.
Failing fuel pump
Dirty mass airflow sensor
Restricted catalytic converter
Dirty fuel injectors
Worn spark plugs
Ignition coil failing
The proof image shows a fuel pressure measure tool. In this case, the pressure falls to 11 psi, causing long engine cranks.
A customer dropped off their vehicle after noticing it cranked excessively before starting. They reported that the vehicle ran without problems and was quick to restart. However, the problem would always return the next day.
The technician noticed an extended crank on the test drive before the engine started, but it turned over reasonably. During the vehicle health inspection, the technician found no issues with the battery and noted that the charging system tested well.
After additional diagnostics were authorized, the technician tested the fuel pressure with a mechanical fuel gauge at the fuel rail. The fuel pressure was at manufacturer specifications with the key on and the engine off. When cranked and started, the vehicle maintained the fuel pressure. However, when turning it off, the fuel pressure dropped significantly. When restarting the car, the pressure slowly rose to a reasonable level.
The technician then blocked the return line to the fuel tank when it passed the pressure regulator to verify that the failure was in the fuel pump and not the pressure regulator itself. With the key in and the engine off, the pressure returned to normal, but once turning off the vehicle again, the pressure drastically fell, verifying the failure was in the fuel pump. It would need replacement.
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This proof image shows a mass airflow sensor. In this case, the red arrow points to debris, which causes the "check engine" light to flash.
A customer dropped off their vehicle after noticing its check engine light active for about two weeks. Finally, they reported that the vehicle drove and started fine. The technician checked the gas cap and found it tightly put, which didn't seem to be the cause.
The technician noticed the check engine light was on after a test drive but didn't find other issues. Likewise, the technician noticed nothing about the customers' concerns during the vehicle health inspection. However, after performing a vehicle code scan, they found a code indicating a mass air flow circuit range or performance problem.
After additional diagnostics were authorized, the technician used a vehicle-specific scanner to verify the code. On a test drive with another technician, while driving at 45 miles per hour and applying wide open throttle, the load only reached 71%, where it should be at least 85%. This low value indicates an issue with the dust or defective mass air flow sensor.
The technician then accessed the mass airflow sensor and found it very dirty. They cleaned the sensor using a dedicated cleaning fluid and reinstalled it. After clearing the code and performing another test drive, they found that the engine's calculating load was 92%. The dirty mass airflow sensor was the issue.
2/6
The proof image shows that the inside of a catalytic converter has debris restricting operating capacity.
After noticing their exhaust smelled like rotten eggs, a customer dropped off their vehicle at the shop.
Although they didn't notice any smell, their daughter reported a rotten egg scent from the car. They also told the technician that the "check engine" light had been on for a month. However, they weren't sure if these issues were related.
The technician noticed a lack of acceleration on the test drive and confirmed that the check engine light was on. The technician didn't notice any problems related to the symptoms during the vehicle health inspection
A vehicle code scan returned a code for the catalyst system functioning below the ideal threshold. After the customer authorized additional diagnostics, the technician tested the catalytic converter with thermal imaging. This test showed that the internal temperature was higher than the outlet temperature.
To confirm if the catalytic converter was clogged, the technician removed and analyzed it, confirming it was restricted and causing the smell. Therefore, the catalytic converter would need replacement.
Replacing a catalytic converter is necessary if it is no longer effective. In this case, it wasn't effective since it clogged. Although certain cleaning chemicals claim to be effective, they often fail to resolve the issue once the converter is clogged.
3/6
The proof image is of a removed fuel injector. The red arrow is pointing to a dirty tip. Clogged fuel injectors commonly cause issues in the engine.
A customer dropped off their vehicle after noticing that the RPM gauge bounced around while idling. The customer also notified the shop that the "check engine" light had been on for weeks.
The technician took a test drive and noticed that the check engine light was on, and the engine felt like it was misfiring at idle. The technician ran a vehicle health inspection and found a code indicating a misfire on cylinder number four.
After the additional diagnostics were authorized, the technician used a dedicated vehicle-specific scanner and found a high rate of misfires on the cylinder. The technician removed the number four spark plug and found significant raw fuel on the electrode. The spark plug on cylinder number three looked normal with minimal wear.
The technician checked the cylinder compression on numbers 3 and 4 and found they were within manufacturer specifications and 2% of each other. After switching the spark plugs and coils of the two cylinders, the technician restarted the vehicle to check for live misfires on the scanner and found that they stayed with cylinder four. The technician then removed the fuel injectors for those cylinders and found significant debris on both tips. After switching the injectors on three and four and restarting the vehicle, they found that the misfire was now on cylinder number 3, thus proving that the injector now in number 3 was the problem.
The technician performed a fuel injector cleaning service authorized by the customer. After the injector cleaning service and clearing the codes, the technician found no remaining misfires on any cylinders.
4/6
The proof image compares the failing spark plug to a brand-new one, improving the overall car engine.
A customer noticed they had been getting poorer fuel economy and believed the problem was the low quality of the fuel. The technician performed a test drive and a vehicle health inspection but didn't notice anything wrong with the vehicle's performance apart from more vibrations than usual. But, they noticed a check engine light.
Once additional tests were authorized, the technician used a vehicle-specific scanner. Unfortunately, the test didn't return any specific trouble codes. Instead, when the technician used the scanner to check for misfiring in the engine, they found random misfires across various cylinders.
When the technician removed the spark plugs for inspection, they noticed considerable wear. The technician measured the space between the center and ground electrodes and recorded 65 thousands of an inch when the manufacturer's specification for that plug was 45 thousand.
The technician performed a compression test on all cylinders and found no more than a 2% variance from the specifications for that engine. The technician recommended replacing the spark plugs and the spark plug boots, as there were some carbon tracking stains on the boots. Regardless of the vehicle type, if you drive an American or Japanese car, these issues are likely to happen if you're behind on inspections.
The technician also recommended a fuel service to clean injectors as preventative maintenance.
5/6
The proof image shows the location of the failed cylinder. In this case, the failed part was the 5th ignition coil, which affected the whole ignition system, causing engine sputters.
A customer dropped off their vehicle after noticing it chugging or sputtering while driving. When this happened, the check engine light would flash, and the light had been on for about a week.
On a test drive, the technician confirmed that the check engine light was on and that the vehicle started to sputter during acceleration.
The technician did not notice anything related to the customer's concern during a vehicle health inspection but found a misfire code when performing a vehicle code scan.
After the additional diagnostics were authorized, the technician used a dedicated vehicle-specific scanner and found a continuous misfire on a cylinder. After removing and inspecting the cylinder-related spark plug, the technician found it damp with fuel. Next, the technician removed and inspected other spark plugs, which were normal.
Then, the technician performed a compression test on two cylinders and found that the compression was within the manufacturer's specifications. Next, the technician switched the cylinder-related spark plugs' places. Then, they also took the spark plug wire from a cylinder, switched it with another, and reinstalled everything. Finally, the technician started the vehicle and found the misfire stayed on the problematic cylinder.
The technician then switched only the ignition coils and found the misfire had moved, proving that the coil on the problematic cylinder failed and needed replacement.
6/6Typical Fixes to Address the Cause(s)
The following chapters bases themselves on experiences from our auto repair shop; we'll describe related problems' causes and fixes.
The AutoTechIQ ranking for Safety, Cost Avoidance, and Environmental Impact is
Vehicle Symptoms
Below are just a few examples of typical Symptoms and Fixes your car might be experiencing
Other things your auto repair shop might talk about:
Exhaust manifold. Failing catalytic converter. The engine is sputtering. Oxygen sensor. Combustion chamber. Carbon monoxide. Vacuum leak. Engine intake system. Carbon dioxide. Exhaust leak. fuel filter. clogged fuel filter