Hello, my 2022 nightshade mpg had dropped drastically. I serviced the transmission at 55,000 miles and had new tires, Yokohama avid ascend put on and my mpg dropped by over 5 mpg. I was getting 49 to 50 mpg and I am now getting 45 to 46. Side note. My car say adverage of 48 mpg, but when I calculate it based on miles and gallons its 45 to 46 mpg. They are times, like in heavy rain I got 38 mpg and cold mornings , say around 40 degrees, I get 42 mpg. I had it a Toyota twice and they say everything is fine. I am not sure it is. Any suggestions
What were the original tyres? New tyres will alter the mpg depending on what type you choose. (And also, new Tyres will need a break in but it won’t be as dramatic as 5mpg. Probably more like 1-2mpg).
Normal is not really a thing. There are many factors involved, including location, weather, driving style, topography, trip types, and etc. Low rolling resistance tyres can add 3-7 mpg or so, depending on what they are replacing. If you look on mpg websites, you’ll see averages for your vehicle. 44 is right there for most Prius, but you can do better or worse
