|
That first tank was awful low at 18mpg as compared to the epa numbers. I bet you filled the previous tank on the uphill side of the pump and did not pump it as full as the current one. Todays gas tanks are pretty flat and it can make a big difference which side of the pump you fill from.
In my old corrolla, 87 and 89 were about the same MPG and 91 5% worse. I ran 89 cause it would never ping that way and I figured retarding the timing would be worse for MPG
In my current CRX HF the gas mileage at freeway speeds is pretty much the same for all grades, but at low RPM cruising, 45 MPH, 5th gear, 1400 rpm for example, there seems to be about a 5% increased MPG per grade according to my supermid and my last 3 tanks.
|