gas milage

NOPE

No

Premium gasoline does have a slightly higher BTU content than regular but the difference in mileage is virtually undetectable. If your engine is tuned for the better gasoline using regular could impact mpg as the electronic ignition may need to retard the spark to prevent detonation (knock sensor). Premium gasoline (branded) has a better detergent package and you would gain some benefit from cleaner injectors, etc.

Now remove the ethanol and you get better mileage.

NO

People in the oil industry also know this, but their advertising companies will be happy to hear people can be convinced other wise.

I get the most effect when I run a couple tanks of injector cleaner through. Usually get 1-2 MPG better.

DougE wrote:
Premium gasoline does have a slightly higher BTU content than regular but the difference in mileage is virtually undetectable. If your engine is tuned for the better gasoline using regular could impact mpg as the electronic ignition may need to retard the spark to prevent detonation (knock sensor). Premium gasoline (branded) has a better detergent package and you would gain some benefit from cleaner injectors, etc.

Premium actually has LOWER btu than regular. Regular burns hotter and faster.

Only difference I've ever seen in mpgs from different gas blends is between using gas with some ethanol vs 100% straight gas. Straight gas will give a little better mpgs generally. But as with anything related to mpgs its almost impossible to get a perfect apples to apples comparison.

No

BTW I don't generally get better mpgs with a certain brand, though I tend to favor shell gas if prices are the same as the place across the street. BUT I will say my mpgs SUFFER greatly when using gas bought on an Indian reservation. Even with Indian gas being way cheaper it still doesn't come out better in a cost per mile.

srt20 wrote:
BTW I don't generally get better mpgs with a certain brand, though I tend to favor shell gas if prices are the same as the place across the street. BUT I will say my mpgs SUFFER greatly when using gas bought on an Indian reservation. Even with Indian gas being way cheaper it still doesn't come out better in a cost per mile.

I guess that depends on the indian reservation. Have heard the same thing here, but my car's engine (both cars) can't tell the difference. By the way, before I retired from hauling fuel, I loaded side by side the rigs that hauled the "indian res" gas and can say for sure that the gas was the same gas that the off res stations got. The only difference was tax on it.

But my cars can tell the difference between regular (with ethanol) and premium (without ethanol). The Honda much prefers the premium, gaining 6 mpg and the Ford only gains 2 mpg. I quit making special trips to the Res and buy my gas where ever I need it. My motorhome does not use gas.