Check Engine Light Comes On When Accelerating (Cause & Fix)
So you have noticed your check engine coming on whenever you accelerate? Are you wondering why this happens and whether you should be worried? If yes, this article will give you the answers to all your questions.
Check engine light comes on when accelerating due to a cylinder misfire which is most likely caused by a malfunctioning ignition coil, bad ignition wire, or faulty spark plug. A diagnostic test will help you determine which cylinder is misfiring and confirm whether the issue is caused by the ignition coil.
Our full guide below will discuss more details on why the check engine light comes on when you’re accelerating and how to fix it. We’ll also discuss approx. how much it costs to solve this issue and other helpful info you need to know.
Why check engine light comes on when accelerating
Engine misfire is the main culprit behind the check engine light flashing whenever you accelerate. Misfires can happen due to various reasons including a dirty fuel filter, cracked spark plug, cracked distributor cap, bad spark plug wires, and so on.
We don’t recommend you continue operating your car when this happens because it may end up causing costlier damages such as catalytic converter damage, which is expensive to repair or replace.
Misfires during acceleration are also not good for everyone on the road as they can lead to accidents.
When misfires occur when your vehicle is under load while you’re pressing the accelerator, it may result in slow or sluggish acceleration, and your car may experience trouble getting up to speed. You might feel a jerking motion as you try pressing down on the throttle.
Worn-out spark plugs are one of the most common causes of misfires during acceleration. When they undergo excessive wear, spark plugs are unable to ignite fuel in piston cylinder at the time they’re supposed to. This issue can also be caused by the other issues we have mentioned above.
When ignition of fuel in piston cylinder fails, regardless of what causes it, coil voltage is restricted from jumping the spark plug gap—creating an engine misfire while you’re accelerating.
Various other systems of your car such as air intake and fuel injection system rely on the throttle position sensor (TPS) to provide accurate data.
When this sensor is faulty or you have dirty fuel injectors, your car engine may also misfire during acceleration, and a check engine light will show up. Your vehicle may also go into limp mode after this happens.
For the older vehicle modes, Your Mechanic explains that the reason for misfires is usually caused by the ignition system. This is because the vehicle lacks sophisticated sensors than can result in a misfire.
This is unlike in modern vehicles which feature CEL light to tell you exactly which cylinder is to blame for the misfire and what part of the engine is related to the misfire.
What to do when check engine light comes on when accelerating?
If you notice your check engine light flashing when accelerating, you shouldn’t continue driving your car as doing so can cause more catastrophic damage to your car and can also be a danger to all the people on the road.
You should take your car to the nearest auto mechanic and have them carry diagnostic tests on it to find out what issue the engine is experiencing.
A professional repair shop will scan your car computer for diagnostic trouble codes that triggered the check engine light to come on.
While these codes won’t tell your mechanic the exact issue your car engine is experiencing, they’ll prove quite useful to them when it comes to diagnosing what is behind the engine misfire.
Also, depending on what diagnostic tool your mechanic uses, it may indicate the number of misfires that occurred with a given number of drive cycles, or your engine RPM when the misfire happens.
Keep in mind that some misfires will not cause trouble codes to be logged into your computer memory, especially if the misfire is imminent.
The mechanic will then conduct tests on specific parts or components to help them accurately determine what the underlying problem is and recommend the best repair possible.
PRO TIP: Providing your mechanic with any additional info will prove helpful in diagnosing your car. If you noticed any peculiar sounds or behavior when driving your car, and how frequently the misfires occur during acceleration, be sure to mention all this to your mechanic. The more information you provide, the easier it becomes for them to find out the cause of the misfire.
How much does it cost to fix the check engine light coming on when accelerating?
The cost generally ranges anywhere from $100 to $1000plus. As we have just said above, engine misfires during acceleration can be caused by a variety of reasons such as the cost of fixing this issue will greatly vary depending on the cause of the misfire.
If the misfires are caused by worn out spark plugs, you just need to replace them with new ones which go for around $150. Bad spark plug wires will cost you $100 to $300 to fix. Faulty ignition coil will cost you around $150 to $250. A fuel injector will cost you $275 to $400.
If a vacuum leak caused the misfire, you’ll be spending around $200 to $800. Broken valve springs cost $450-$650 to fix. Broken piston rings causing misfires will cost you a whopping $1500 to $3000.
As you can see, it is hard to say how much check engine light illuminating while accelerating will cost you until the mechanic has diagnosed your car and found out what is causing it to misfire.
Not to forget, your mechanic will also charge you around $60 to $100 for diagnostic costs on top of the repair costs.
What does it mean when check engine light comes on under hard acceleration?
Check engine light flashing under hard acceleration could be due to fuel starvation issue and may have something to do with a faulty mass airflow sensor (MAF).
The sensor regulates air intake into your car engine and then relays this info into your car computer. The computer system then adjusts the amount of fuel being supplied to match.
Thus, if the MAF isn’t working properly, it will lead to a fuel starvation issue. When this happens, you’ll normally experience a slight hesitation in your car’s accelerating power.
Hard acceleration can also cause a misfire. If in addition to the warning light you also experience a bumpy and jerky motion during hard acceleration, this could be a sign of engine misfire.
Changing all the coils and spark plugs can clear this problem and make your car run like it’s new again.
However, we still insist that the best way to deal with this issue is taking in your car for a diagnostic test to find out what problem activated the check engine light and have it fixed.
Why does check engine light come on while accelerating uphill?
If the check engine light comes on whenever you go up the mountains or hit the uphill section of the freeway, this is usually a fuel starvation issue.
When the engine triggers a check engine light on a hill, it means it is being starved of the amount of fuel it requires to go uphill.
This could be due to something as simple as the fuel filter that needs to be changed. Or it could be due to the mass airflow or ignition coils/spark plugs issue.
When going uphill, your car needs more gas, air, etc., so the warning light coming on means it is not getting what it needs.
As we always advise you, it’s best to drive the car to an auto repair shop to have them pull the fault codes that triggered the CEL.
This will help determine what exactly caused the light to come on and give the mechanic a clue on what needs to be worked on to clear the light.
What if the light flashes for a while and then stops during acceleration?
A flashing check engine light usually indicates a cylinder is misfiring. As we have said multiple times before, misfires should be taken care of quickly.
If not given immediate attention, they can cause more damage to your engine parts including the catalytic converter, resulting in additional costly repairs.
Even if the CEL flashes and then stops during acceleration, you shouldn’t continue driving your car to avoid causing further damage to the engine.
You should instead have an auto mechanic carry a diagnostic test on the car to establish what issue it is suffering from and fix it for you, of course at a cost.
If you’re experiencing check engine light when accelerating, it could be a sign of a problem with your car’s engine, transmission system, or fuel system. However, this issue could also be associated with other common problems, such as issues after rain or after a car wash. To learn more about these potential causes and what you can do to fix them, check out our articles on check engine light after rain and check engine light after car wash. These articles provide helpful tips and insights on how to troubleshoot and solve these issues, so you can ensure the safety and reliability of your vehicle and prevent any further damage.Frequently Asked Questions:
This is a clear indicator you have an engine misfire which can be caused by various issues including the ignition coil, dirty fuel filter, cracked spark plug, and so on. when this happens, you should have your car diagnosed by an auto mechanic to find out what exactly is causing your cylinder to misfire and have it fixed to clear off the check engine light.
Your check engine light starts flashing when you go over 70 mph to indicate that one of the engines is misfiring. However, the best way to deal with this issue is to have your car scanned for the stored trouble codes.
These will not only pinpoint the exact cause but will help the mechanic in finding out what causing the misfire and offer the best possible repair to your car.
Definitely. Continuing to drive your car when it’s misfiring is a bad idea as it can result in serious damage to your engine such as catalytic converter damage, which is expensive to fix. You should have your car checked by an auto mechanic when the warning light comes on when accelerating.
Otherwise, the longer you wait to have it checked, the more damage the engine suffers. In the worst-case scenario, continued engine misfire will result in costly damages that could even destroy your engine.
Final Verdict
Now you know why your car’s check engine light comes on whenever you try accelerating. This issue is usually caused by engine misfires. The engine misfires can be a result of many issues including weak ignition coils, bad ignition wiring, worn-out spark plugs, and so on. In older vehicles, it is usually due to an ignition system as these cars don’t have sophisticated sensors that can create misfires.
When your car flashes during acceleration, we suggest that you should stop driving it to avoid causing more damage to your engine. Instead, you should have an auto mechanic diagnose it to find out what is behind the misfires and repair them to clear off the CEL. Remember, the cost of a misfire can be anywhere from $100 to $1000+, depending on the reason behind the misfire.
