It’s frustrating when suddenly your vehicle doesn’t accelerate as fast as you want. Just yesterday everything was OK, but now the car doesn’t want to speed up. Also, you can see that check engine light on the dashboard. What should it mean?
In short, if your vehicle shows the check engine light and the acceleration is very slow, the problem can be with one of the sensors, with ignition, fuel supply, or timing system. The engine may misfire, and the air-fuel mixture may be too lean or too rich. One more possible issue is that the transmission is freaking out.
I haven’t listed all the possible problems that can turn on the check engine light and affect the acceleration in your vehicle. This is just the list with some examples of these problems.
The best way to understand what’s going on with your car is to use the OBD2 scanner to read the code that seats behind the check engine light. If you read this code and understand what it means, you can easily see the actual problem with the engine or any other unit in your vehicle.
Your actions when the car doesn’t accelerate and shows the check engine light
First of all, I want to tell you what exactly you should do if you get into such a situation with your car.
You need to remember that not in all cases you can drive the vehicle further. This can just be dangerous for the engine and other components of the car. Also, you need to make sure that none of the vital units is affected by the problem.
Here is what you can do even if you don’t have any tools with you:
- make sure that there is no error message on the dash of your car;
- stop the car in a safe place, turn off the engine, and let it sit for a while;
- start the engine again and see if the problem disappeared;
- register all the symptoms that you feel your vehicle has right now;
- try driving your vehicle carefully without accelerating it really fast.
If you still feel that something is wrong with the car, it may be a good idea to stop the vehicle and drive further only after you are sure that nothing important is affected. Sometimes, slow acceleration along with the check engine light may show some serious problems with the engine or the transmission.
If you have an OBD2 scanner of any kind, you can get much more information. Just connect your scanner to the OBD2 port in your car, and you will have access to the codes that triggered the check engine light. Read the codes and google them to find out what exactly malfunctions in the vehicle.
What are the most common reasons for poor acceleration and check engine light?
When you notice that your car is not accelerating like usual, you may want to press the gas pedal even harder. But this is the last thing you should do at this moment. First of all, you need to find out what’s wrong with your car.
I’ve prepared the list of the most common problems that can affect the acceleration of your vehicle and also turn on the check engine light on the dash. Here are the most common problems:
1. Engine misfiring
If your engine is misfiring, it means that one or several cylinders don’t work as they should. There are different reasons that can cause misfires, the most common of them are problems with the ignition, bad spark plugs, faulty ignition coils, problems with the wiring, and also issues with the ECU.
Your engine may misfire because it has lost compression. If one of the cylinders doesn’t have the needed compression, the fuel will not ignite. As a result, the engine will work without one cylinder. This leads to significant power loss, that’s why your acceleration may be so bad. And also, this triggers the check engine light.
2. Low fuel pressure
Modern vehicles work with quite high pressure of fuel. Especially the direct injection engines which have two fuel pumps. If one of the pumps fails and the pressure in the fuel injectors is low, the engine will lose power and probably won’t start at all. But the engine with the port injection will still start and work even if the pressure of the fuel is low. Of course, in such a situation, the engine will not develop all the power it can give you when the pressure is normal.
It’s not that easy to check the fuel pressure. But professionals will do this using the code scanner. The low fuel pressure usually means that the fuel pump is not working correctly and is probably going to die soon.
3. Engine sensors are faulty
By engine sensors I mean the sensors that control and operate the throttle. Also, some other sensors that affect the work of the engine can trigger the check engine light and also affect the overall work of the engine making it less efficient.
Usually, it’s quite easy to locate the problem if you have the OBD2 scanner. The code that sits behind the check engine light will tell you everything. Without the scanner, you are not likely to identify the problem quickly. One of the possible methods is to turn the sensors on and off hoping to find the faulty one. This will take some time and also will require some knowledge of where these sensors are located.
If one of the sensors is faulty, you should replace it with the new one. Always buy OEM sensors because they will live longer and will operate your engine the way it should be operated.
4. Damaged engine
One more possible reason why your engine doesn’t want to accelerate your vehicle is that the engine is not healthy. One of the parts of the engine may be cracked or some components may not be working properly.
For example, a crack in the piston may result in bad compression in a certain cylinder. Or the problem with the head gasket can lead to issues with cooling or oil supply in the engine.
5. Timing system problem
The engine is a very tender machine. It works thanks to very precise timing. If the timing is changed, the engine will not work efficiently or will not work at all.
The timing in the modern engine is ensured by the belt or the chain. Unfortunately, these belts and chains don’t live forever. Sometimes, you will need to replace them along with the tensioners, water pumps, and some other elements.
But the timing chain or belt can jump one tooth if it’s stretched and the tensioner can compensate for this stretching anymore. If the belt or chain jumps one tooth, the engine will still work, but its efficiency will be close to zero. Your check engine light will be on, and the acceleration will be completely sluggish.
6. Transmission problems
You shouldn’t concentrate on the engine alone if you see the check engine light and the car doesn’t accelerate as it should. One more unit that can be in charge in this situation is the transmission.
Whatever kind and type of transmission you have in your car, it’s probably not going to leave as long as the engine. On one bad day, your transmission may ask for repair or even replacement. Some problems with the torque converter or with the clutch may trigger the check engine light and may also affect the acceleration.
Signs that you should stop your car immediately
In most cases, when your car hesitates during acceleration and shows the check engine light on the dash, you can keep driving without high risks for your engine and other units in the vehicle.
But there are some signs that tell you that is better to stop now. Here they are:
- You hear the grinding noise from the engine bay. This may mean that your engine or transmission is in poor condition and can break fatally at any moment.
- You see the error message on the dash telling you to stop immediately. Don’t ignore these messages because they are usually connected to some safety features or they may be trying to prevent some of the important units in your car from failing.
- The car stalls and you lose control right in the middle of the road. Driving such a vehicle is not safe and it can eventually lead to accidents and other unwanted road situations.
- The power of the engine is so poor that it can’t accelerate even in the first gear. It means that something important is faulty in the engine and you should stop and avoid driving further until you understand what the problem is.
Also, I recommend stopping the car in a safe place if the problem happened unexpectedly right when you are driving on the road. If the issue has been developing for quite a long time, you can still drive to the repair shop or the dealership. But once it happened unexpectedly, you should stop and try all the methods that I have listed above in this article to locate and maybe even solve the problem immediately.
Final thoughts
It’s not a pleasant experience when your car hesitates during acceleration and shows you the check engine light on the dash. When this happens, you may expect to spend some money on expensive repairs and diagnostics.
But after reading this article, you have much more ideas than just calling a tow truck and towing the car to the dealership. I hope you can figure out what’s wrong with your car and avoid spending hundreds on professional diagnosis.
If you still have some questions on the topic, please ask them in the comments section below.