Symptoms of Bad Gas In Your Car (& How to Get Rid Of It)
June 7, 2022

Michael Collado is a car buying expert and has been a professional automotive writer since 2009. He’s written about dealership sales, vehicle reviews and comparisons, and service and maintenance for over 100 national automotive dealerships. Previously, Collado was a copywriter at the ad agency TBWA/Chiat/Day where he worked on brand campaigns for Nissan, ABC Television, Sony PlayStation, and Energizer. His recognition in the ad industry includes awards from Communication Arts and The Clios.
Collado has a Bachelor’s degree from the University of South Florida, with a major in Psychology and a minor in Marketing.
Are you having trouble with your vehicle’s performance? It may be the quality of the gas in your tank.
That’s why it is important to know the symptoms of bad gas in your vehicle.
We'll take a look at what warning signs you should look out for. Additionally, we'll review how to get rid of bad gas from your tank.
Table of Contents
What Causes Gas to Go Bad?
Gas can go bad if it sits in your tank for an extended period. Auto experts estimate that gas can go bad after three months. This is because the gas begins to break down and it will become less effective in the engine.
Signs That You Have Bad Gas in Your Car
Symptoms of bad gas can include engine stalling and startup issues, lack of acceleration, a lit check engine light, and more.
Engine Stalling
If your engine is slowing down its operation or no longer functioning, then it is in the process of stalling. This can happen if you are attempting to drive with old or bad gasoline in the tank.
Engine Start-up Issues
Let’s say you have had a car that has been sitting in your garage for months. If you try to start up the vehicle, the gasoline may have degraded to a point that it will not be able to turn over the engine.
Lack of Acceleration
The quality of gasoline plays a big role in the performance of the vehicle. For instance, high octane gas is required for exotic sports cars. Therefore, if you are driving with bad gasoline, your engine will not have the proper fuel that it needs to deliver the desired acceleration.
Check Engine Light
Anytime there is an issue with the vehicle’s engine, your vehicle’s check engine light will come on. This can typically happen when you are driving with bad gasoline in the vehicle. When this happens, it is a good idea to go to a service center and have the vehicle inspected with a diagnostic scan tool.
Delayed Gear Shifting
Bad gasoline will affect just about every part of your vehicle’s performance. This will include the transmission and the vehicle’s ability to shift gears. If you notice that gears are slipping, then you may have bad gas in the vehicle.
Burn More Gas
Bad gas will be diluted and it will not be as effective as good gasoline. Therefore, you will need to burn more gas just to maintain the normal operation of the vehicle. This could lead to more trips to the fuel station.
How to Avoid Contaminated Gas
You don’t want to end up with contaminated gas in your vehicle. Therefore it is important to take the right steps to avoid contaminated gas:
Avoid Leaving Gas in Your Tank for More Than Three Months
If you are planning to garage or store your vehicle for more than three months, then you will want to drain the tank.
Use High-Quality Gas
It is always a good idea to use high-quality gas. This is especially true if you drive a high-performance vehicle. The better the gas, the better the performance.
Use a Fuel Additive
Be sure to add a fuel additive that can help protect the quality of the gas in your tank.
Testing for Bad Gas
Make sure you know when you have bad gas in your vehicle. You can test for bad gas by swapping the gas and checking how much water is in the gasoline. If there is a higher than usual concentration of water in the gas, then it is considered “bad” and the vehicle gas tank will need to be drained.
How to Remove Bad Gas From Your Car
Once you have determined that there is bad gas in your tank, you will need to have the gas tank drained. Here is the four-step process to getting the job done.
1. Remove Gas Tank
The first thing that you will need to do is remove the gas tank from the vehicle.
2. Siphon Gas From the Tank
After the gas tank has been removed, then a siphoning tube can be used to remove the gas from the tank until the tank is completely emptied.
3. Add Dry Gasoline
Now add dry gasoline. This is an alcohol-based additive that helps treat gas tanks that have been contaminated.
4. High Octane Gasoline
Finally, fill up your gas tank with high octane gasoline. Even if you don’t have a high-performance vehicle, you will want to make sure that your engine is receiving the highest quality gas so it can provide better performance after being contaminated with bad gas.
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Frequently Asked Questions
Can bad gas damage your car?
Bad gas can damage your vehicle by degrading performance. Also, bad gas can cause issues with the fuel filter and the fuel pump. That’s because the fuel filter can become dirtier faster. Also, the fuel pump may have to work harder to feed gas to the engine.
Can you get reimbursed for bad gasoline?
If you can prove that you received bad gasoline from a fuel station, then you should be able to be reimbursed for the price of the gas. However, you may have to pursue legal action to be compensated for any damage to the vehicle.
What are the symptoms that you have water in your tank?
Symptoms of bad gas in your tank include engine stalling, failure for the engine to start up, decreased acceleration, declared fuel efficiency, a check engine light, and delayed gearshifting.
What is the best type of gas for most cars?
The better the gas, the better performance you will get from your vehicle. For most vehicles, that will be gas with an octane rating of 89 or better.
What happens if you drive with bad gas?
If you drive with bad gas in your car, you can experience decreased performance. Over time, you can damage parts of your vehicle such as the fuel filter and the fuel pump.
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