Premium Gas

If a car says to put in premium gas do you have to or can you use unleaded gas?

Even premium gas is unleaded. Tetra Ethyl Lead has not been allowed in automotive gasoline since the advent of the catalytic converter.

Premium gas has better antiknock ability than regular. If your owner/operator manual specifies that premium ‘must’ be used, you shouldn’t use regular. If the manual specifies that premium is ‘recommended’, you could use regular but the performance and fuel economy will be less. In the later case, the engine ECM will be retarding the ignition timing whenever it senses detonation. If detonation becomes severe, damage to the engine is possible.

Hope that helps you. Reply with the exact wording of the owner/operator’s manual instructions and we can give you a better opinion on your use of regular gas. Also the make, model, engine size, mileage, and useage of this vehicle would help.

Premium means just what it says; your car is designed to run most efficienty on premium. In an emergency you can use regular, and the engine will adjust the computer to avoid knock. However that’s not a good long term solution; like breathing through only one nostril!

Premium gas is unleaded gas, so I assume you mean, “can I use regular unleaded instead of premium”? If your owner’s manual says it is required to use premium in the car, then you should use it. In general you will get better performance in these cars than if you go down to regular unleaded.

If the manual says premium is recommended (not required), then regular unleaded may be an acceptable solution.

As noted if the manual or a sticker on the car says to use premium failure to do so could damage the car. It also is likely to reduce power (likely one reason you chose that car and likely reduce mileage, eliminating any savings you might get on the price of the gas. Note: generally using premium on a car designed for regular will not increase power or mileage.

Here’s a an article on the subject. The results are surprising

You can use regular fuel however the results vary completely on vehicle, engine type, condition, driving style, and other factors. I guess it is a 10% premium in price over regular fuel currently. When prices were high($4/gall+) it was a paltry 5% more.

I would use premium until it is out of warranty, even if only recommended. If you use a lower octane rating than recommended or required in the owner’s manual, you are giving the manufacturer an excuse to void your warranty. Consider it cheap insurance.

How cheap? If premium is 10 cents more per gallon and you use 12 gallons per week, you will spend an extra $1.20 each week. That’s an extra $62.40 every year. That seems like a minimal expense to run the car the way it was designed.

Not a bad report.

Does your owner’s manual recommend high octane gas or is it required? If it is only recommended, using cheaper gas should not damage anything. If the owner’s manual requires high octane gas, use high octane gas. You don’t want to ruin a car to save a few bucks on its fuel.

What, [i]specifically[/i], does your owner’s manual say on the subject?

I owned a 1993 Ford Probe GT. Premium gas was recommended. I generally used regular or midgrade (I know a couple of stations that sell midgrade at the same price as regular). I bought the car new, owned it 10 years and put 210,000 miles on it. I never had any engine/performance problems (the car had two tuneups). I was curious and once checked the difference in MPG between regular and premium (regular = 26 MPG and premium = 27 MPG). Sooo…I opted to save some money and use the cheaper fuel - never had any problem!

Sure! Sure! Sure! Those reports all ignore a basic fact: The knock sensing system, the spark control system, and fuel delivery system WON’T always perform flawlessly. As systems age, the probability of something going wrong increases.
The results of something going wrong can be something as simple an the engine turned to junk. How much of a gambler are you?
As Dirty Harry said, “Do you feel LUCKY?! Well, do you?!”.