I have a 2015 Honda Accord EX and wondering if anyone with similar has monitored gas mileage with regular vs premium gas? Previously I owned an Accord Hybrid (the model they only made for a couple of years) and I saw a significant difference in mileage with premium (90 or above) gas. I did the math and found I actually saved money by using the higher octane gas.
I haven’t closely monitored with the current car but tried using mid grade for awhile and doesn’t seem to be a big difference. However, I haven’t closely tracked it, mainly because my driving fluctuates between highway and city so much that it’s hard to really track if there’s a difference.

 

It will not make a difference. Before I flashed my ECU I gradually moved over to premium gas in preparation over a few identical trips out of town and saw no difference in gas mileage. Just cost more to fill up.