Can Premium Gas Cause Misfires?

There are vehicles that recommend that motorists use premium gas.

However, in most of those vehicles, you can use regular gas and you will still have no problem. 

For many years, motorists have seen premium gas as a way to clean fuel injectors when the injectors could catch a lot of dirt, making them ineffective in their work. 

Does premium gas affect your regular gas vehicle? 

Can Premium Fuel Cause Misfires?

Premium gas will not cause a misfire in a regular gas vehicle unless your engine already has a problem. High-octane gas, also known as premium gas, is high-grade gas, and it will give you the same performance as you get with regular gas. 

Read on to learn more about premium gas and its effect on your vehicle. 

Will Premium Gas Mess Up My Engine?

Premium gas has a high-octane rating, 91 or more. This is high compared to the 87 rating of regular gas. 

The gas has more gasoline compared to regular gas, which makes it more resistant to early ignition and is, therefore, able to stop damages to the engine. 

If you use premium gas, your engine might stop knocking, but that will only be treating the symptom and not the disease. 

However, if your car doesn’t have any misfires, using premium gas will not have any effects on your car’s performance or engine condition. 

In engines that have a high compression ratio or turbochargers, premium gasoline will help reduce engine pre-ignition and misfires. 

In such vehicles, you can still use regular gas, but you might see reduced performance. 

However, pre-ignition might still occur, causing the engine to knock and ping, which might lead to further damage. 

How Do You Tell When a Vehicle Has Misfires?

Bad gas can cause misfires. However, using premium gas is less likely the cause that you have misfires in your car.

There are several ways to tell whether you have a misfire. 

The most common sign of misfires is rough acceleration or rough idle. You may see the check engine light or your engine might perform poorly. 

The check engine light might keep blinking whenever there is a misfire.

When a misfire occurs, you may feel the engine jerk. This misfire occurs when the car is under load and you accelerate hard.

If your car is on high gears, it is easier to notice this kind of misfire. 

In some instances, the engine gets a rough idle. 

If the sensors get faulty valves, the air-fuel mixture does not burn as needed, and this causes uneven idle.

Even the smallest air-fuel mixture problems will cause the vehicle to experience a rough idle, making this the first place that you will notice misfires. 

Vibrations are also a common sign of misfires. When a cylinder or more does not fire as needed, the engine loses its balance and vibrations become common.

A check engine light is a notification to drivers that something is amiss with the engine.

Vehicle engines come with all sorts of sensors to help detect problems in the engine before they exacerbate. 

When the check engine light comes on, it means you have a problem, which might be engine misfiring. 

You might also notice slow acceleration or the engine sound will change. If you notice any of the symptoms above, then you have an engine misfire. 

Can 87 Gas Cause Misfire?

Regular gas, 87 octane rating, will cause a misfire if used in a high compression engine or turbochargers. 

High-octane gas prevents early ignition in these high-performance engines. 

If your vehicle has a high-performance engine, the 87 octane fuel will ignite from the heat released during the compression stroke. 

When the fuel ignites, the engine computer system registers that as a misfire. 

The unburned gases flow down the catalytic converter, and they are burned off. 

There are still unburned gases inside the converter and these will raise the temperatures in there too much that some parts might even melt. 

When the 87 gas detonates, it causes the engine to knock. This is detected by the engine’s knock sensor.

The computer will adjust the timing after the knocking to match the combustion with the actual spark event. 

By adjusting the timing of the spark plug, the engine will have less power and its fuel economy will also suffer.

Because modern engines are advanced, there will not be any damages to the engine except the reduced performance. 

In some instances, you will also see the check engine light come on showing misfire codes. 

To ensure this does not happen, stick to premium gas for vehicles that recommend it.

You will protect the catalytic converter and also get the high performance the car was engineered for. 

What Happens If I Fill My Regular Gas Engine with High-Octane Gas?

If the automaker for your car recommends 87 octane and you accidentally put 93 octane, nothing will happen. 

The high octane gas is just a different blend of gas that does not have much effect on the performance or the condition of your engine. 

The gas will burn differently in a regular gas engine. High octane gas is harder to ignite, and your engine will need to apply more pressure to it.

However, when combustion occurs, it does so in a more powerful and efficient manner in turbochargers. 

In regular gas engines, adding premium gas will have no significant effect. 

In some instances, your engine may not burn the high octane gas efficiently, leading to a drop in gas mileage and reduced power.

Will Mixing Premium and Regular Gas Cause Check Engine Light?

It is possible to mix fuels with a different octane rating. 

When the two fuels mix well, you will get gas with an average octane rating. 

For instance, if you mix 87 octane and 91 octane, you get 89 octane rating if you mix equal volumes of the fuels. 

The mixed blends will not have significant effects on the performance of your vehicle.

For high performance vehicles, the mixed fuels may cause misfires. 

Some engines can adjust the timing of the spark plugs, but some engines may still knock, and, in worse cases, damage the catalytic converter. 

Does Bad Gas Cause a Misfire?

Bad gas can cause a misfire. The bad gas restricts the flow rate of fuel, leading to an inappropriate ratio of fuel to air. 

This wrong air/fuel ratio results in insufficient power to start your car’s engine causing a misfire. 

Old gas is an example of bad gas that can result in a misfire. The old fuel can clog the fuel filter, resulting in low fuel pressure. 

When the engine does not get enough fuel to start, a misfire occurs. 

Older fuel is lighter as most of the volatile compounds in the fuel will have evaporated.

This leads to sapping engine power and can even cause stalling. 

The duration it takes gas to go bad in a car is dependent in the type of the gas and the usage. 

Most types of gas will start to go bad after three months. As a rule of thumb, you should not use the gas in your tank if it is more than a year old. 

Old gas will not damage your engine instantly, but if you continue using it, the gas will eventually cause damages to the engine. The engine starts to misfire and can eventually fail. 

Closing Thoughts

If you notice that the gas in your vehicle causes a misfire, you may need to empty the tank and remove this bad gas. 

Most modern engines will adapt their operations to the octane rating of the fuel and will not likely sustain any damages.

However, in the case of old gas, even the modern engines might experience clogging problems. 

Talk to a mechanic if you notice engine knocking or you experience effects on performance. 

To avoid all these challenges and protect your engine, stick to the octane rating that the automaker recommends.