Saving money with Regular Gas in your Premium car?...Better do the math.

Note that two out of eight (25%) cars saw a decrease in mpg when using premium gasoline. Not a statistically strong correlation for using premium gas. Probably a combination of varying driving styles and that octane is not supposed to affect mileage for modern cars.[1]

[1] http://dsc.discovery.com/cars/top-10/car-myths/08.html

This article doesn't really say much, does it? Averaging fuel consumption in daily driving isn't a very good testing method because of variations in conditions.

It's really not that difficult of a decision for me. According to the engineers that designed and built my engine, I should use fuel rated at 91 octane or better. Why should I presume that I know better than those engineers? Imagine if you, as an engineer, told a client they should not use a particular technology because it is unsuitable. Then, imagine the client flatly ignored your suggestion. That'd be pretty frustrating, right? So why do that with the advice of automobile engineers?

My 1995 car (premium at the time) diesels horribly on the cheap stuff so I don't use it; the cost of repair is probably going to overwhelm any savings, given my driving habits.

Which I suppose is exactly his point; do the actual math. Don't step over dollars picking up pennies.

Why are there 2 Infiniti G 35's listed with opposing data? In the first case you get better mileage with premium, the next one shows you get better mileage with regular. This really makes all the data look very suspect.

Ah, weasel words I love thee: "...potential for long term damage..."