Yours is an auto or a manual? What specs bro? Where're you from, perhaps we can yum-cha?

Oh like this will be East meets West bro >.<

Mine manual fc after 4 days into my delivery is about 18km/l only, I'm still exploring!

i think no la..
the conventional auto gearbox if i remember correctly by someone who explained it to me, he said, the gearbox is not mechanically connected to the engine.. the thing that will wear is the clutch plate..
but during idle speed, i think the torque is still nothing if compared to torque during wheel spin,  (in manual, full throttle, then dump clutch in 1st gear)

take two table fan facing each other, and let one of them rotate freely..
if u turn on the 1st fan, the other fan will follow if enough airspeed pushes its fan blades..
but if u set the fan speed slow, the other fan will not follow-turn. because not enough airspeed to spin the blade..

air in the fan equals to gearbox oil in our auto gearbox,
and the first fan is the engine, the 2nd fan (free rotating) is our gearbox,
so in gear D during idle, can say it is at the ngam ngam speed to rotate the 2nd fan, if we apply more fuel, engine rpm rise, and the 2nd fan blade (our gearbox will rotate)

so the torque at idle is only little..
but if the red light too long, just put in N lah, so u will not feel the vibration..

i think the vibration is coming from the "air" (gb oil) that passes the 2nd fan blade (torque converter), but u stop the 2nd blade with ur hand (apply brake to car), the air still passes through the 2nd fan blades and struggling to rotate the 2nd fan blade,  but since the torque so little, and u hold the blade, it wont move, but u will feel the vibration abit laa.. its like a small kid try to move a big fat guy.. 

The Axia FC seems amazing. But wonder why it varies largely from 11km/L until 30km/L pun ada. Other car makes  normally also show the average speed that achieved that FC. Like Toyota or even proton will show both the FC and the average speed for that measured range. So, if you claim your FC is 30km/L but your average speed is 90km/h it makes more sense because others with FC 16km/L might have an average speed of 40km/h only... Heck, my innova at ave speed of 90km/h can make 16km/L and you know how thirsty Innova is   My daily commute to work and doing runaround average speed is around 30km/h per fill up. I want to know one full tank of Axia with that average speed can achieve what FC. Then I have pretty good idea what FC of Axia is ...  takut nanti sudah beli tengok FC 12 km/L rasa disappointed pulak eh