Hi, i drive a K12 too.
I might have the solution for you but you must try it and not
listen to others or read too much comics on K12.
1)Ease off on the gas pedal abit.(you're letting the RPM
drop)
immediately,
2) Floor the gas pedal all the way.(You're forcing/shocking the
engine to shift gear)
and you will get the surge.
If you feel no surge and there is a lag by trying the above.
Try doing this:
3) Turn off the aircon
and repeat step 1(Ease off on the gas abit more), 2(once you HEAR
the engine rpm drop then "Pedal to the Metal")
You will have to do this a couple of times in order to know your
car as to why it is not shifting gear(s) and to have a better
understanding of your car's behaviour.
Unfortunately there isn't a Tachometer/ air-fuel ratio gauge in
your car or else you will know how
hard you are driving/pushing it.
Call me @9760 7170 and i will demostrate the abovementioned if you
are still in a fix after trying.
Books and listening to what other(s) tell you is a fairy tale,
experience is what counts to know your car.l
Cheers Bro,
lennie