Three months after new, I took a four week trip overseas, and parked the car. Before I left the ECO worked as I expected, and I was averaging 7.2 - 7.8 l/100 combined city/highway. The instantaneous indicator also seemed to work well. Light acceleration showed about 13 - 15 l/100 for a few seconds, foot off gas was 0.0 or 1.1 with a/c on.

I read in the manual the car goes into hibernation after 14 days of no activity.

Coming home, the car woke up as I approached, started normal and drove normal. Then (a few days later) I noticed the ECO instantaneous was reading 9 - 12 l/100 in normal driving. The average crept up to 9.2 and stayed there. As I gently accelerated the display would shoot up to 30 or even 60 l/100 then back down to 9 - 12 but fluctuating wildly.

As I took my foot off the gas, it would go to 0.0 but as I come to a stop, it shoots up to 15 - 20 l/100 then back down to 0.0 l/100.

Over this last summer the average slowly dropped to 8.8 l/100, but the display still give wild readings. Toyota dealer test drove this car 3 times and said it seemed normal (???) and said they can do nothing more. He could not compare it to a same 2014 model as it was 2015 and they had none on site to test.