[ChevyColorado]

I sometimes use fuel additives that "improve gas mileage" in my gas tank, but after doing the math I realized, It's just not worth it. The 5 bucks you pay for a bottle of this stuff only get you another 10 - 15 miles or so per tank. For that, you could just put in $5 worth of gas and probably get more than that. Any opinions on this?

[Buyer]

Yes. Over time, without the additives your mileage would get worse. The additives are cleaners-they remove the crud from inside the engine that makes it inefficient.

You could just buy a higher quality fuel, spend the five bucks on that. Same effect, they have the additives in already.

[TBird65]

I just buy the mid grade fuel. Wish I could afford the top notch stuff, but gas prices are just to high. Buyer's right though, the better fuel you buy th more mileage you will get.

[Pedal2theMetal]

I use the high grade stuff. I used to use lower grade gas, but after i found out you can get for for your money with the good stuff, I started using it.

[ChevyColorado]

Maybe I should just start using the mid or high grade fuels....? Never really even considered it because of the price, but I guess it's time to make that change. Man, these prices are a real killer!

[JackSwagger]

I am also using the mid grade one, want to use the higher one, but the cost of it puts a lots of effect on the salary. Hope soon i will be able to use that.

used Cadillac engine

[RoadWarrior]

Guys, this just isn't true. The only time you need to use a higher octane gas is when the car manufacturer requires it. It doesn't have more "additives," just more octane. All grades of gas contain the same amount of detergents to keep your fuel system clean. You're ripping yourself off and wasting money by buying higher octane gas when you don't need it. Seriously!

Chevy, instead of buying "additives," try this. Pour one cup of rubbing alcohol into the gas tank. It won't hurt and it'll clean the fuel system.