Is Premium gas really needed?

[shortimer]

I have used 89 octane for long trips, mostly highway miles, and did not notice anything unusual. When I do burn the 89 octane I add it to my tank when it still has half a tank of the 93 octane. I've never burned the 87 octane.

[mscmor]

THT - I like the explanation. Thanks. I was wondering if there is any negative effect of running a consistant 93 octane fuel containg a small percentage of Ethanol. I think Sunoco advertizes 10% ethanol in their selections...
MSC

[THT]

Nope. Just don't switch between blends and non-blends otherwise you'll gum up your cat.

~THT

[getgopi]

I agree. Stick to one grade of gas. I have always used Premium on my 1996 Maxima. I get upto 33 mpg on the highway and 24 mpg in a mix of city (45%) and highway (55%) driving. Plus the car continues to have excellent passing and pickup power. I might have used Regular or Special gas a couple of times (when the gas station ran out of Premium). Last Friday, I decided to use Special because of all the rising fuel costs. On Monday, the check engine light came on and Midas told me it was the upstream oxygen sensor acting up. Only last month, I had replaced all 3 exhaust pipes, downstream oxygen sensor, muffler and catalytic converter for $1140. But since my car's performance and mileage seem fine, I am going to just follow the suggestion from another thread (go to http://www.automotiveforums.com/vbul...=oxygen+sensor and look for a post by gregory4041), run the car for a few days and see if the check engine light goes away.

[JDM_ONLY]

On MAXIMAs/I30,I35 91 octane is recommmmmended (nissan is a tq base Vehicle) and to prolong the longitivity of the ENGINE. But check this out... you could insert 87octane w/ 10% Ethanol; dyno both respectively and oddly the second fuel mixture will output more Tq's and Hp's then 93 octane.

[THT]

Got a dyno sheet of a VQ30 to prove that?

~THT

[shortimer]

Greetings,
Just got back from the NY Auto Show. During the trip I put 360 miles on my '02 I35. I used 89 octane for the entire trip and the car ran fine. I've been using 89 octane for several months with no problem. I talked with an Infiniti service tech and asked him if using 89 octane instead of 92 octane could damage the O2 sensors or any other emissions equipment. He told me the 89 octane was okay to use. I have to agree with the service guy. The car does not ping under hard acceleration and that would be an early warning that the octane was too low. I'm staying with 89 octane for now. I'll let you folks know if I have problems. By the way, I use "name brand" gas like Gulf, Citgo or Sunoco.
Regards,
Shortimer

[Ceasars Chariot]

use at least 91