I have driven the Coquihalla Highway several times in the Micra - I had the Manual transmission. Most of the time I could keep hwy speeds in 5th gear. The long steep grade at Box Canyon did provide a challenge for the Micra (as it does for most cars) but I was able to keep 80 K in 3rd with no problem. The Okanogan connector (97 C) with it's very long accent out of Peach-land to the peak was a challenge and I was not able to maintain the speed limit of 110 hm/h. However, I was able to maintain 100 km/h in 4th gear for all of it. I also work at a Ski Resort on Vancouver Island and used the Micra to commute up the mountain. I found it very capable and easy to keep control on the steep downhill sections in winter. The Micra manual definitely could use a 6th gear - I found traveling at or near our 120 km/h hwy speed limit a little loud and fuel economy suffers. Mind you, not sure if I really want to go faster than 120 km/h in something with an 8 foot wheel base!
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View my fuel log 2015 Micra sv manual: 6.9 L/100 km ... 40.8 mpg (Imp) ... 14.4 km/L ... 34.0 mpg (US) ...