I Accidentally Put Premium Gas In My Car: What Happens Next?
I put premium gas in regular car, is it harmful? No, It is not harmful.
Your car requires regular, unleaded gas to run efficiently and effectively. Premium gas, while it might sound like a good idea since it’s more expensive, actually isn’t necessary at all. In reality, premium gasoline doesn’t offer any benefits on your regular car that would improve your car’s performance or lifespan.
There’s no question that premium gas costs more than regular gas, but will it hurt my car if I put premium gas in it? If you’re wondering about this, have a sigh. We found at least ten forums where people asked this question, and not everyone seemed to get the same answer.
So let’s dig in and see what we can find out.
What If You Use Premium Gas In Regular Car?
Most carmakers design their engines to run on regular unleaded gasoline with an octane rating of 87. That said, you’ll occasionally see gas stations offering 87, 89, and 91 octane levels. The higher the octane rating, the more resistant it is to pinging or knocking during the combustion caused by the air/fuel mixture detonating prematurely in the engine.
Modern cars are designed to be able to use up to 93 octane fuel, though most recommend using 87 because it offers better mileage and performance than premium fuels.
Premium gas will not improve your vehicle’s performance in most cases. It just prevents pre-ignition knock or pinging that might damage the engine over time. But if you continue feeding your regular gas car that is not used to with premium, a question of threatening the engine can arise.
In other words, if you’re already running 87-grade gasoline in your car but keep filling up at a station that only sells 91-gas, then you’re probably wasting money. However, if you’ve noticed pinging from driving past an area where they sell premium gas (signs usually say premium or super), going there once in a while won’t hurt anything.
To be more clear on this, you can also know the other side’s answer, like what happens if you put 87 octane in a 91 octane car.
What Happens After Putting Premium Gas In Regular Car?
Many people believe that using premium fuel in a regular car can damage the engine. As premium gas has a higher octane rating.
However, there’s no evidence to support this claim. In reality, premium gas does not damage your car engine. But, most modern cars are designed to run on regular gas without any problems. So what happens if you accidentally put premium gas in a car that takes regular gas?
It Prevents pre-ignition knock or pinging:
If your regular car engine suffers from pre-ignition knocking or pinging, putting premium oil can help with that. Octane ratings measure an engine fuel’s resistance to pre-ignition knock or pinging. If an engine runs low on octane and experiences knocking, adding more octane would make it easier for the engine to fire at lower compression ratios and avoid knocking.
It helps clean carbon deposition from engine pistons
Another reason some people often put premium gas in their regular cars is to help clean carbon deposits from the engine pistons.
It reduces wear and tears on spark plugs
Regular engines don’t have spark plugs explicitly made for high-octane gas. So, they tend to burn hotter and produce more exhaust gasses, leading to increased wear and tear on spark plugs by using premium oil. It can help reduce the wear and tear on spark plugs.
Premium fuel contains additives that help protect against sludge buildup
One last benefit of using premium fuel is the additive package which helps to prevent sludge buildup. Sludge buildup refers to a buildup of varnish and other unburned materials that cause engine clogging. Sludging occurs when you mix unburned material with gasoline while the latter is still raw. Sludging decreases combustion efficiency lowers power output and damages engine parts by blocking lubrication channels. For these reasons, using premium fuel rather than regular will help reduce sludging as well as other potential engine malfunctions.
Note: Make sure your car engine is capable enough to run on premium gas.
Better acceleration and throttle response
Mixing both might be worth considering if you are using a flex-fuel engine (either E85 or Flex Fuel) since many users report better acceleration and throttle response. As long as you are not using a car that requires only premium fuel (like Mercedes), using it in your regular car should not cause any harm.
What Threats Can It Create?
1. A waste of time
Unless you’re driving an older car with carburetors, using premium gas instead of regular won’t fix anything that needs fixing.
2. Decrease performance and fuel economy
Some motorists may experience reduced fuel economy or performance after switching to high-octane gasoline. Though according to research, this reduction isn’t significant enough to justify paying extra for premium fuel in your car.
3. You are wasting your money
Premium gasoline costs more than lower grades of gasoline. It means putting them in a vehicle could increase your monthly fuel bill significantly, and you are just wasting that money. That is because a regular car engine is designed to use regular fuel and cannot take advantage of premium fuel.
Pro Tip: Use the right type of gas – don’t let someone tell you to put premium gas in your regular car. There may be a small performance boost but you’re also going to pay about 30% more per gallon for it.
Frequently Asked Questions (FAQs)
What happens if you use premium gas?
We’ve all been there. You’re at the gas station, filling up your car, and you accidentally grab the wrong nozzle. Before you know it, premium gas is pumping into your tank. But what happens next? First, don’t panic. It’s not the end, and your car will probably be just fine. Second, if your car is designed to run on regular gas, you’ll probably notice a decrease in performance and fuel economy.
Can premium gas hurt my car?
If you’re driving a car that requires regular gas, the higher octane in premium gas won’t hurt your car. However, it will be a waste of money because the higher octane does nothing to increase performance in a car that doesn’t require it. In fact, using premium gas in a car that doesn’t require it can decrease performance and fuel economy. So, if you accidentally use premium-grade gas in your regular car, don’t worry – you haven’t done any damage.
What happens if you run premium gas instead of regular?
If it happens accidentally, don’t worry – you’re not going to do any damage. The higher octane in premium gas won’t hurt your car but won’t provide any benefits. You’ll just be wasting your money. So next time, make sure you check the pump before you fill it up.
Is it worth switching from regular gas to premium gas?
Whether it is worth switching from regular gas to premium gas depends on factors such as the age and model of your car, where you live, how much driving you do per year, etc. But for general purposes, if you use a regular fueled car, we recommend sticking with cheaper standard grade gasoline unless you notice a significant decline in performance over time.
Final Thoughts
What happens if you accidentally use premium gas in a regular car? Just don’t freak out. It is not going to do any damage to your car, and you’ll be just fine. However, if you’re looking to save some money, it’s worth sticking to the lower octane gas that your car recommends. Higher-octane gas will cost more, and your engine may not need it.
You Can Also Read:
- 1 Gallon Of Gas In 32 Gallons Of Diesel: Can You Mix Them Up?
- What Number Is Premium Unleaded Gas & Their Advantages
- Is Diesel Better Than Gas For The Environment? How?
- Is Unleaded Gas Regular Gas Or Mixing It Can Be a Disaster?

Pattinson used to be a mechanic in his early life. And most of his life was spent working in a garage next to his house. That is where he finds his interest in working with motor vehicles and their parts. Pattinson does the core part of Motor Mav write-ups that plays the part of keeping your reading flow in track by proofreading all the articles and ensuring the proper use of words and tune. Apart from this, he nowadays enjoys his retirement by maintaining his yard with landscaping tools.