Question

What is DTC 1117 Nissan Micra (K12, Model Year 2005) ?
It can't be the engine coolant temperature
sensor, because the engine doesn't enter fail-safe mode and he only comes in connection with an excessive idle speed. Unless the accelerator pedal is released and the engine can enter idle mode, nothing happens.
The engine warms up normally to its lowest idle speed (about 800 rpm)
but then the reverse process begins and the idle speed slowly and steadily increases (regardless if being let in idle mode or driven and stopped from time to time).
At about 2000 rpm the revolution suddenly wavers
and henceforth the engine runs with 800 rpm and no
activity at the oxygen sensor.
It sounds strange now because of the
too lean mixture.
When the accelerator pedal is depressed the engine stammers but
suddenly picks up speed and can be driven normally again. Also the oxygen sensor shows activity again.

Any intake error or a defective oxygen sensor can definitely be excluded
(The operation of the oxygen sensor was monitored with the help of an external meter).
Perhaps the timing-chain because it lengthens while it warms up together with the engine ? Early Micra's (K12) were prone to timing-chain lenghtening and the symptoms hereby were indefinite.