it'll misfire under heavier load. power will be down across the board. fuel economy will suffer.With modern knock sensors i doubt it will knock but power will be down at least 15% or more.
this is the guideline i relay to my customers. i use costco in my STI.I have a question on premium fuel and if one brand is better than the next. I have some choices in my area including Shell, which I have read is recommended by Ferrari. Is that just marketing or is there something unique about their premium blend. I'm talking USA gasoline, not "petrol". Thanks.
After driving a Ghibli 2 years and 20,000 miles I've always used plus, 89 octane, not premium. Used premium a few times especially now with gas as cheap as it is but see no difference in power or mileage. Never had knocking.
agreed. ~2bucks per tank difference for a properly functioning, as designed, vehicle?