Hello everyone, Today I took our Prius to the highway for the first time, and I have to report that I'm highly disappointed in its MPG. It was a 62 mile trip, with at most 10 of these miles driving in the city. According to the display that shows in place of the HSI when the car was turned off, trip time was 1h39min, although I estimate I spent somewhere around 20-25 minutes in city driving conditions. Hence I estimate my average speed was 42 mph or so -- it was nearly midnight and the road was as close to empty as they come so it was perfectly safe to drive that slowly. Again according to the end of trip display, trip fuel consumption was 3.9 l/100 km which works out to about 60 mpg. This was a deep disappointment for me -- before leaving I was pretty sure 70 mpg was guaranteed with these driving conditions, and my honest expectation was 80 mpg or more. For context, outside temperature was 18ºC (64ºF), all windows were closed, and no air conditioning/heating (only sporadically and just for a few seconds each time for defogging the windshield). Since the trip was fairly short, it's worth noting that the car was semi-warm at the start of the trip -- it went into Stage 4 after driving less than a mile. Tires were at 40 psi front/36 psi rear, just had them pumped yesterday. Cargo weight was about 500 pounds (myself, my wife and a bit of luggage). For instrumentation I have an OBD-II WiFi dongle with the EngineLink app for iPhone. I was mostly monitoring RPM. Driving technique was pulse and warp stealth, trying to keep the pulses within the ECO area (1400 RPM-1800 RPM), only rarely going up to 2200-2400 RPM at the steepest inclines. When EV mode was available I tried avoiding it. Also, when going down hills, rather than regen braking I just let the car coast in warp stealth mode, even sometimes exceeding the speed limit (to avoid the losses associated with conversion to electrical energy). In short, I think I went by the hypermiling book and was frankly expecting much better mileage. I just have no idea what I could have done better here. For the return trip I will just set the cruise control at the same 42 mph (conditions permitting) and will see how it does, just in case there's something seriously wrong with my driving technique. My best hypothesis for the crappy mileage is the sorry excuse for fuel that is available here in Brazil: regular gas with 27% ethanol content. Going purely by energy content, it's about 10% less than pure gas, but still, that'd mean someone doing the same trip, at the same speeds, using the same technique, would be getting 66 mpg or so -- whereas, from what I've read here, under the driving conditions outlined above, something like 90 mpg should be doable, if not even more. I'm pretty sure the ECU maps are pretty screwed up due to the insane amount of ethanol in our fuel, burning fuel in a way that's much less efficient than the 10% energy content difference would suggest. Either that or there's something seriously wrong with my car. I intend to let this tank drop to nearly empty and then fill up with premium gas for the next few tanks to see if it makes any difference. I'm aware it shouldn't, yet maybe the fact that our premium gas has "only" 25% ethanol, versus 27% ethanol in regular gas, might help a little bit. I appreciate any thoughts, suggestions or hypotheses anyone may have regarding this situation.