Do higher grades of gasoline help improve gas mileage?

Question

current cars are-

2000 Jeep Grand Cheerokee (12 mpg)

2002 Chevy malibu (about 20 mpg)

Answer 1

waste of money all gas is the same the trucks are different the grade wont matter put in what you manufacture recommends you will be pooring money down the drain doing anything else honest

Answer 2

No. I've read several articles on cars stating that higher grades of gas don't improve mileage. Check your owners manual to make sure what grade of  gas you should use. The majority of vehicles only need 87 octane. There are only a few cars that require higher grades of gas such as sports cars like Corvette and premium luxury cars like Infiniti which my Dad drives. I think those types of cars require higher grades for performance, not mileage, purposes. If you put a higher grade of gas in your car then 87, which is probably all you need on your vehicles, it won't hurt anything but it will be like throwing your money away.

Answer 3

No.

Answer 4

No,,, only cost more, and if any improvement

would be lost in the higher cost of the fuel.

Answer 5

well premuim gas only gaurantees cleaner engine/ if it help gas milage maybe 10%

jeep would increase to 14 mpg?

chevy maybe 22 mpg?

you put additives in tank to do same from parts store! about same cost or less!

Answer 6

No.  Higher octane ratings (which aren't really "grades" per se) just mean there are more slightly longer hydrocarbons which ignite at higher temperatures and pressures.  This prevents pre-ignition...fuel exploding to early, which causes "knock," which is parts that should be sliding across one another smacking into one another.  

However, different engines are designed to use different octane ratings.  High-compression engines (usually found in sports cars) need high-octane gasoline to prevent their higher pressures from causing knock.  Your cars were designed for regular 87 octane gasoline.  High-octane gas will work, but it will not do you any good whatsoever.

The only time you want to use high-octane gasoline in a low-octane engine is if you're getting knock.  Carbon deposits in the cylinders can cause this by retaining heat, causing the fuel-air mix to get too hot, too fast.  High-octane gas can reduce this effect and thus be a temporary fix.  

BTW, you really need to learn how to drive if you're getting fuel economy like that, in both your cars.  Seriously, there is something wrong with your right foot.

Answer 7

no it doesnt all it does is help your engine running longer.

Answer 8

that's what they say.

lol.

Answer 9

not at all. it's a waste of money. don't bother with it