Just wanted to get back to the forum re: my lousy MPG when I first got the car. I tried removing my roof rack, inflating the tires more, engine block heater, and was already driving slowly, coasting as much as possible before anticipated stops, etc. I am sure each of these items helped (the grill blocking most, and EBH 2nd). Prior to grill blocking, I got as bad as 18-22mpg per tank the first winter. After doing everything I had suggested, I only broke 50mpg for one or two trips the first year. Somewhere around 17,000 miles, I started getting much better mileage whether I tried or not. I got around 50.5 mpg all the way from Michigan to Virginia Beach last Summer --often going 75mph on the interstates. I need to try putting the Thule Aerobar roof rack back on & see if it affects mpg much. Toyota's tech support told me that PREMIUM fuel WILL definitely help mpg, but CONSUMER REPORTS said it doesn't make a difference. I'm inclined to doubt consumer reports. Thanks again to everyone who made helpful suggestions - esp. to Wayne Mitchell & Evan Fusco (& not the guy who blamed my mpg on me being an obvious 'leadfoot')... Mark
I doubt premium fuel will help at all. It contains less energy then regular. The prius is not designed to use premium fuel, thus it can't take advantage of the higher compress-ability of premium to generate more power.
Wow, 18-20mpg? I would have taken it in for service at that point. I have 700 miles on my Prius. I am driving in 20 degree weather here in New England and I am getting currently 47.2mpg. (48 on the last tank)
I too can't see how premium fuel would make any difference. Now, I can definitely see how "bad gas" could lower the fuel economy, but regular 87 octane fuel as long as it is good fuel, should be perfect.
Premium fuel should help, but IT'S NOT WORTH THE PRICE DIFFERENCE. That's what Consumer Reports means - the performance increase is tiny, and is much, much smaller (percentage-wise) than difference you pay per gallon.
Hi Mark, See the Hybrid13 Fuel and EVAP System.pdf file on autoshop101.com which provides numerous Toyota tech training documents. Page 3-4 of that document recommends use of 87-octane regular unleaded gasoline and says, "Do not use premium gasoline. It may cause starting problems with the Prius. There is no gas mileage benefit when using premium gas!" Regarding your problems with low mpg until your car logged 17K miles, I am wondering if your rear parking brake was dragging slightly, and this finally cleared after your car logged that many miles.
Toyota, or some dealer's employee? In either case that is not what Toyota's documentation says. Save your money.
