G35TOIS350

Ran a tank of mid grade vs prem and got a bit better mileage. Same toll road with the cruise set at 80. Prem tank got 21mpg and the mid-grade got 24. Am I nuts or can the lower oct give you better mileage?

PhilipMSPT

iTrader: (5)

There are a lot of factors that contribute to gas mileage. Temperature, traffic, tire pressure, road conditions, use of a/c, time to warm up a car, etc, as well as fuel grade.

I think fuel grade is not a "major" factor to gas mileage, but rather the conditions in which the car travels.

al503

you also have to take into account pump differences. Different pumps will click off at different levels. However, that is a pretty big disparity.

GreyHound

iTrader: (1)

Damn Man, they would throw you under the jail here in Virginia if you got caught doing 80
Well if you happen to slow down a bit to around 65, you might be able to get 31 or 32 MPG, if its flat land. I did going to the beach in NC. Only had to rumble a little bit around Raleigh( to keep from getting run over). the 350 does real well with fuel mileage, and power
be careful out there.

e-man

The same thing happened to me last year (GS 400). I can't explain it, but it was a noticeable difference. I keep track of gas mileage religiously, and I usually get 20.5 to 21.5 on every tank. On the tank where I used the lower octane gas, I got 23.

flipside909

Lower octane fuels work better in higher elevations.

t0e

iTrader: (1)

It is also noted in the manual, if the engine detects lower grade gas octane (sorry) , the fuel injection process runs differently.

paeko73

What is "lower grade gas mileage"?

93 LS4

87 burns quicker then 93, you will get better gas mileage with the good stuff.