[chrbut]

Has anyone tried different gas then the recommended 91 Octane on the 05 GTO? at over $2.00/gal its hard to keep filling up with Premium.

 

[Xman]

I've run 87, 89, 91, and 93. I wouldn't run 87 long term but I had no problem with knocking when I've used it which I expected because of the anti-knock sensor.

 

[Afterglow]

I used 87 a couple times, the car seems slightly sluggish when using 87 and gas mileage drops a bit. I just stick with 91-93 now. I have noticed the best gas mileage with BP and Speedway gas. That's mostly highway miles with a lead foot. Just my $.02

 

[GTODEALER]

93 is the ONLY way to go!!!!!!!!!!!!!!!!! I feel sorry for people on the west coast.

 

[roadracer]

Once after working 28 straight hours I filled up and realized I had put 87 in the tank. It ran without any knocks are problems, but I still always use 91 or better.

 

[tmcclaff]

93 is the ONLY way to go!!!!!!!!!!!!!!!!! I feel sorry for people on the west coast.

:agree I wouldn't use anything less then 91. This is the same engine that is in the Corvette go over to their forum and ask about using 87