I have a 1995 Dodge caravan 3.0 with 158K miles on it (not all mine). This summer, I have tried premium (93 octane) because the car had no power to speak of and was only getting 18-19 mpg. Since changing to premium (8 weeks and 3500 miles ago, I have averaged 23 mpg (27 high, 21 low) and have saved about $60 assuming 19 mpg on regular - this when premium costs between 20 & 30 cents more per gallon than regular where I am. I have not changed my driving habits (that I know of). Additionally, the engine accelerates smoothly now (instead of hesitating at every upshift) and can maintain 70 mph at about 2200 rpm (it was needing 3000 rpm on regular).
I’m sold…I have had cars in the past where premium made no difference at all and have always thought that there was no difference…