I won't lie: the 4-speed automatic is still driving me nuts.
Ironically, two of the Micra's closest competitors (Chevy Spark and Mitsubishi Mirage) use more efficient CVT's sourced from Nissan/JATCO. GM just switched from a 4AT to the CVT for the current model year and saw a big bump in fuel economy as a result.
Nissan says they're using the 4-speed to keep costs down. Unfortunately that means automatic buyers save a few bucks up front, but pay more in the long run through higher fuel consumption.
It's pleasant enough to drive -- shifts are imperceptible under light to moderate throttle. And car reviewers like stepped transmissions more than CVT's.
Fuel economy features
At least the torque converter locks up in 3rd and 4th gears.
And it's got pretty aggressive DFCO. Release the throttle in 3rd or 4th and it instantly cuts fuel. It will even downshift from 4th to 3rd during fuel cut deceleration. That's a neat trick - can't do that in a manual without burning a bit of fuel while you change gears.
This style of DFCO will probably benefit "average" drivers who tend to do very little coasting. Binary driving: either accelerating/cruising or braking.
But I have sometimes found myself going to N to get much longer coasts, even though the engine is idling. If I had the car for a longer time, I'd do some comparisons to confirm that's a good strategy.
Also, it can get very slightly herky-jerky when you're cruising at very light throttle, as it will trip into DFCO, then back out again if you're near that threshold.
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Currently sitting at 5.2 L/100 km (45 mpg US) indicated after ~400 km. Subject to calibration. The proportion of sub/ex/urban driving is rising. Again, this is with basic ecodriving. Nothing my mother wouldn't do.