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Can Bad Gas Cause a Misfire? (All You Need to Know)

If you are familiar with driving or car instrument, you might have heard about misfiring. Generally, a misfire in a car can lead to short and long-term problems. Sometimes, the problems are so severe that the engine might fail. On the other hand, bad gas in your car can also lead to different problems.

So, you might be confused about whether bad gas can cause a misfire. Well, you should know about the connection between the gas line and the engine. Besides, knowing the problems caused by bad gas is essential. Otherwise, you can’t solve the problem of bad gas in your car.

Can bad gas cause a misfire?

Bad gas can cause a misfire. When the fuel tank has bad gas, it will restrict the fuel flow rate constant. This will lead to an inappropriate air to fuel ratio. If there is a wrong air/fuel ratio, this will cause insufficient power to start the engine. So, a misfire might occur due to bad gas.

However, the term “bad gas” might represent different stages of bad. For example, it might be old fuel or low-grade fuel. So, different stages of bad gas might cause different problems. Moreover, they might cause a misfire in a different way. So, let’s see whether these bad gases can cause misfires or not.

Wrong octane gas cause misfire:

A wrong octane gas can cause a misfire. Generally, misfire is a situation when the cylinder or engine doesn’t get enough power to start. So, when there is a problem with the fuel or gas, it might cause a misfire. Because the fuel flow has a direct connection with the cylinder and engine.

When you put the wrong octane gas in the fuel tank, the air to fuel ratio will also be incorrect. Wrong octane gas also decreases the fuel economy.

Generally, when you choose the low octane fuel, it will ignite early. So, the engine and cylinder will remain in a misbalance. That’s why a wrong octane gas can cause a misfire.

Old fuel cause misfire:

Old fuel gas can also cause a misfire. Especially, if the old fuel is more than a year old. This old fuel or gasoline will lead to many other problems too that can lead to an engine misfire.

Old fuel can lead to clogging of the fuel filter. This will cause low pressure on the fuel flow. As a result, the engine will not get enough fuel flow to start up. So, a misfire can occur.

Besides, the older the fuel, the lighter it will become. That means the volatile compounds of the fuel will evaporate eventually. It will lead to sapping engine power. Moreover, stalling can also occur. Sapping engine power and stalling will also lead to an engine misfire.

So, the indirect problems of an old gas can also lead to a misfire.

Can cheap gas cause a misfire code?

Yes, cheap gas can cause a misfire code. Generally, cheaper gas is not high-quality. So, it will not generate the appropriate functions of high-quality gas.

For example, when you put a cheap gas and try to run your vehicle, the gas might pull in the air and misbalance the air to fuel ratio. Sometimes, cheap gas can become dirty quickly. As a result, dirty or weak gas can clog the fuel filter.

So, all these problems will lead to inappropriate fuel flow to the engine. That’s why the engine might not generate enough power to start. Then a misfire can occur. So, cheap gas can lead to a misfire.

Can premium gas cause misfire?

Generally, premium gas is supposed to be a higher grade and high-quality gas. But sometimes, some indirect problems due to gas can also cause a misfire. For example, if your vehicle has already a problem with a misfire, a premium gas will not solve the problem.

Many people experience the same performance between regular gas and premium gas. So, premium gas is not that better that can prevent misfire. Moreover, a misfire can be caused by many other problems in the fuel and fuel flow.

But it will be better if you don’t use old or bad gas and use premium gas. Because premium gas might work like regular gas. But it will not cause any excess problem like the old and cheap gas.

How long does it take for gas to go bad in a car?

How long it takes for gas to go bad in a car depends on the gas type and usage. Generally, different types of gases have different characteristics. But most of the gases will start to go bad after three months.

Generally, the more you use the gas, the more it will go bad. Because when you use the vehicle, the volatile compounds of the gas evaporate and the fuel becomes lighter. So, it will go bad eventually. But you should not use the gas after one year.

One-year-old gas might cause different problems in your car.

Can old gas ruin an engine? What harm can old gas do to your car?

An old gas can’t ruin an engine instantly. But it can affect the engine gradually. For example, when the old gas misbalances the fuel flow rate, it will affect the engine. So, the engine will gradually start to misfire. As a result, the engine can fail.

However, old gas can harm your car differently. Let’s see what harm old gas can do to your car.

Misbalance air and fuel ratio:

When you put old gas in your car, the gas will affect the fuel flow to the engine. This old gas can pull air from outside and misbalance the air and fuel ratio. If the air and fuel ratio is misbalanced, different other problems might occur.


When the air and fuel ratio is misbalanced and the fuel flow rate is not correct, it will cause difficulty to start the engine. So, a misfire might occur.

Clogging injectors:

If you use old gas in the car, it will make the fuel filter and injectors dirty quickly. So, the injectors and filters will be clogged. Ultimately, the clogged injectors will affect the engine’s performance.

Damage internal components:

Generally, one part of your car is related to another. So, old gas can cause internal components to be weak. These components will not work at their optimum ability. So, the internal components will be damaged gradually.

What are the symptoms of bad gas in your car?

If your car has bad gas or the gas has gone bad, you might don’t know immediately. So, you have to ensure after seeing the symptoms. Here are some symptoms of bad gas in your car.


When you face difficulty starting your car’s engine or a misfire, it might be the symptom of bad gas. Bad gas can often affect the fuel flow and fuel pressure. So, misfire is a common symptom of bad gas.


Bad gas can create pinging noise. Though pinging noise can be created by other problems. But bad gas can also produce this noise.

Rough idling:

Bad gas can cause rough idling of your car. You will not feel smooth performance while driving your car.


Bad gas can be responsible for stalling your car. Generally, stalling is the sudden slowing or stopping of your vehicle. This can be pretty disturbing. So, stalling can also be a symptom of your car’s bad gas.

How to fix bad gas in a car?

However, when you face the problems of bad gas, you need to fix the problems. Otherwise, bad gas can produce other bigger problems. Let’s see how you can fix bad gas in a car.

  • At first, you have to empty the fuel tank and remove the bad gas.
  • Then you have to siphon out the gas from the tank with a garden hose.
  • Then you can put dry gasoline in the tank that will absorb moisture.
  • After that, you can put high-quality or premium octane gas in the tank.
  • You can also put an octane booster in the tank.
  • Add gas in this process two to three times and the bad gas problem will be fixed.

Final Thoughts

Bad gas can lead to a misfire in your vehicle. Bad gas creates some problems like incorrect air to fuel ratio, clogged injectors, stalling, etc., that can directly or indirectly affect the engine. As a result, the engine will not get the power to start easily. Ultimately, a misfire will occur.