newbie question here. '02 4cyl. 2.7 liter. what is the correct octane fuel for me to run in my truck. haven't gotten an owners manual yet to look it up. the toyota dealer says 87 is fine. am not sure where i saw it but read that minimum of 91 is required. don't have a problem running either one and fuel mileage seems to be unaffected with either. just want to do the right thing as she's got to last me. in my past experience, all 4valves per cylinder engines either should run , or are required to run premium fuel with an octane rating of 91 or better. any help would be greatly appreciated.