Reduced Engine Power After Oil Change [Explained]

When you have an engine with poor performance, you’d naturally try to find the reason behind it. Did you change your engine oil recently and notice reduced engine power after oil change?

That may have you believe that changing the oil has something to do with reduced engine performance. Unfortunately, if you change your engine oil correctly, there’s no reason that it would lead to reduced performance.

reduced engine power after oil change

But when you do it incorrectly, it can cause several performance issues. If you delay the oil change, it can also cause reduced engine performance. Keep reading this article to find out all about it.

Reduced Engine Power After Oil Change [Explained]

Oil change (if done correctly) will never cause reduced engine power. The purpose of oil is to lubricate the different components of the engine. When you top up your engine, it’s meant to prevent your engine components from having direct metal-on-metal contact.

Regular engine oil changes ensure that your engine stays healthy in the long run. But when you make some mistakes, it can performance issues. The most common mistakes people make when changing their engine oil are:

  • Use engine oil of the wrong viscosity.
  • Put in too much oil.
  • Not change the oil filter when changing the oil.

Making these mistakes can cause your car to lose acceleration. Keep reading this guide on car won’t accelerate after oil change to learn more about these issues in detail and how you can fix them.

Apart from these errors, there’s absolutely no reason that you would get reduced engine power because of an oil change. If you do notice it after changing the engine oil, it’s just a coincidence.

Another common question that comes to the mind of most people is a low oil cause reduced engine power. In this case, the answer is yes. That’s because without the presence of sufficient oil, the engine parts won’t be lubricated and that’ll bring down the overall performance of the car.

Modern engines also have some valve timing systems that rely on oil pressure to function. A low level of or dirty engine oil can hamper the performance of such systems and cause a lack of acceleration.

Your car may go into “reduced power” mode when it happens. So if you were wondering can needing an oil change cause reduced engine power, you know exactly why it happens.

What Does Reduced Engine Power Mean

Many vehicles are equipped with a “Reduced Engine Power” light on the dashboard. It warns the driver about a potential failure, sudden loss of power, and impotence to go past a certain RPM.

The reduced engine power mode is often triggered by the PCM of your car when it detects that the flow of fuel or air to the engine is being restricted. It can also be triggered when the PCM detects a system failure in your car.

Generally, whenever you have the reduced engine power light on your car, it’s intentionally limited by the PCM. Even if you don’t notice a reduction in performance right away, it can happen the next you drive your vehicle.

What Causes Reduced Engine Power

Now that you know what the reduced engine power light is and how it works, you’d naturally wonder what causes it. This light is usually a good indicator that you’ll need to do some sort of repair work on the vehicle.

The reduced engine power light doesn’t guarantee that your car will break down if you don’t address it soon but it can lead to major issues in the long run. Here are the common reasons that cause reduced engine power besides your car needing an oil change:

Loose Wiring

There are several electrical components that make your car function properly and any issues in the wiring can cause the reduced engine power light to turn on. Check for a loose ground wire or clamp in your vehicle.

Before checking the wiring, make sure you disconnect the negative terminal of the battery. Check all the wires and reconnect anything that has become unhooked or loose.

Faulty Throttle Position Sensor

The throttle position sensor measures the position of the accelerator when you step on the gas and it uses that information to tell your car’s computer how much the butterfly valve should be opened.

throttle position sensor

This butterfly valve opens up and lets air of the correct proportion enter the engine based on how much your car needs to accelerate. When the sensor fails to communicate with the ECU, the car automatically goes into reduced engine power mode or limp mode. Replacing it should solve the issue.

Data Network Issues

The older vehicles have several modules that work as mini-computers. They can communicate with each other and pass information with the help of a data network. When the data network gets interrupted or goes bad, they can no longer pass important information and the light comes on.

Failing Oxygen Sensor

The main purpose of the oxygen sensors is to measure the amount of oxygen leaving your vehicle through the exhaust system.

They help in maintaining the correct air-fuel mixture by sending that information to the ECU. If one of the oxygen sensors becomes faulty, it can turn on the reduced power light.

The first thing you should try to take care of the problem is to clean the oxygen sensors. If that does the trick, then it’s all well and good. But if cleaning it doesn’t solve the problem, you’ll have to replace the oxygen sensor.

Clogged Catalytic Converter

The job of the catalytic converter is to reduce carbon emissions by converting the carbon monoxide your car produces into carbon dioxide before letting it out to the environment. It’s located under the exhaust manifold in most vehicles and it’s illegal to drive a car without it.

With time, the catalytic converter can become clogged and it can trigger the light. Diagnose if this is causing the issue with an OBII scanner and if it turns out to be the reason, replacing it will solve your problem.

Can Bad Oil Cause Reduced Engine Power

When it comes to the overall health of the engine, not just the quantity of the oil but the quality of it is equally important. When the engine oil in your car is dirty or contaminated, it can cause the engine to run too lean or too rich.

dirty oil or clean oil

So, dirty or bad can cause the reduced engine power light to come on. Thankfully, it’s an easy fix. All you need to do is to drain the existing oil and refill your engine with new oil to turn off the light and drive your car safely.

Can A Bad Battery Cause Reduced Engine Power

Battery issues aren’t the most common reason behind the reduced engine power light turning on but a damaged cell or lose connections can cause it to come on. Fortunately, there are many warning signs before batteries go bad.

The first thing you can do in this situation is to clean the battery terminals if you suspect that they’re corroded. You can use baking soda to clean out any unwanted buildup.

corroded battery

The next thing to do is recharge your battery. If that doesn’t work, you’d have to replace it. It’s not too expensive to replace the battery and you can do it yourself without the help of a mechanic.

Is It Safe To Drive With Reduced Engine Power

While it’s possible to drive your vehicle slowly when you have the reduced engine power light turned on, it’s not recommended that you do it. Driving at such low speeds can be dangerous.

Your ideal course of action when you have this light turned on is to take your car to an auto repair shop as soon as possible. They’ll diagnose the issue with an OBII scanner and inform you on how to fix your car.

How To Reset Reduced Engine Power Light

One way to approach resetting the reduced engine power light is to erase the error codes using a scanner. But you shouldn’t do that as you won’t be able to solve the root cause behind the problem and the light can come back on again.

The way that you should reset this light is to take care of the problem that’s causing it to come on. For example, if it’s happening because you need an oil change, do it so that the light will be turned off.

How Much Does It Cost To Fix Reduced Engine Power

As you already know, there are several reasons that can lead to the reduced engine power problem in your car. How much to fix reduced engine power depends on the reason that’s causing the problem.

For example, replacing the fuel filter can solve the problem for $10-20 if that was causing the issue but if you have to replace the oxygen sensors, it can easily cost you a few hundred dollars.


Now you know that reduced engine power after an oil change is nothing but a myth. An oil change should never cause reduced engine power when it’s done in the right way. However, needing an oil change can cause it, and refilling the engine oil will solve the issue in that case.

Hopefully, you now know about the most common reasons that actually cause the reduced engine light to come on and how you can fix it. Leave a comment below if you have any more questions about the reduced engine power light.

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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