Have 04 Hemi ram that since I bought it about 2 months ago had been running the "Recomended" 89 octane fuel. I was short on cash one day at the pump so I went with the 87 instead. I got like 5 or 6 MPG higher with the 87 than the 89. Has anyone else noticed this?

 

Hello. I use both low and mid octane fuels. I have never really noticed a difference in the two...either performance or gas mileage. I have had my truck for almost 3 months...put 11000 miles on it (95% expressway long distance) and usually push 16/17 mpg at 80+ mph, 20/22 mpg running between 55-63 mph and 13/15.3 between 66-77 mph...a rather weird combination of numbers. But at least I now know what speeds will get me to the next station when I am getting to the quarter tank mark in the middle of a western state. Those numbers run true no matter which grade of fuel I am using or which vendor I am getting it from...shell, chevron, etc.