gas mileage,whats octane should I be using?

[niclar]

I bought my infiniti (1997 I30) used from my uncle and I dont have a manual. Ive had it for about 9mths now and I have been using 89 for gas. With gas prices skyrocketing I want to know for sure which octane I should be using to get the best mileage? I was doing a search and notice other maxima/infiniti owners using premium 91/93 for there cars. While I know this is more expensive but if I can get better milage and performance I will be will to go from plus to premium..Any Thoughts??

[audtatious]

In my 2k2, I get the best mileage with mid-grade or higher. Our cars were not designed to use the lower grades. Try mid-grade and see if you have any hesitation problems or pinging.

Of course, non-jack rabbit starts and driving the speed limit will help...

[maxima278]

will it hurt anything to use 87? I've been using it since gas prices went over $2

[audtatious]

Not necessarily. If you hear pinging, I would suggest upgrading to midgrade. The difference is normally a couple dollars a tank, so it's not that much of an upgrade.

[maxhopper]

It's kind of a wash. Our cars are made to run on premium for optimum performance/mileage. What you save in $by buying the lower grade, you are giving up in performance and sub-par mileage.

[MinisterofDOOM]

Well, my little VG likes midgrade fine The manual for my dad's '04 SE recommends regular. I've seen no difference in performance, or milage with higher grades. I'm not sure about the 3 liter VQ's though... All I know is we got 36 mpg on through southern utah going to Las Vegas on crap 87 octane.

[maxima278]

my 4th gen used to push 30 mpg, but it is in bad need of a tune up. Its down to 23 now. Hopefully since things are looking better in the finances I can change that soon

[niclar]

i have always used midgrade (89) since I got it and just recently I started to notice some hesitation when stepping on the gas but I figured I may need a tune up or an oil change

[audtatious]

De[ends on how many miles you have put on it. I have 89k miles and it is doing just fine, altho not quite as peppy, which is understandable...