Hi Morrogan, thanks for the tip.
Well, it was really bad yesterday morning after I drove it for awhile. Admittedly I was rather aggressive then as I almost took her up to 160km/hr along NPE before she started sputtering as soon as I reached Subang. Funny thing was, I really couldn't reverse nor drive head first into my porch which had a slight slope.
Problem persisted even when I resorted to parking on the flat road just outside my house. Weird thing was, the problem seemingly went away and car shifted like normal after I turned the car off and restarted it.
Even this morning when I drove it to the workshop, it seemed fine, but I didn't really push her >100km/hr. And I was even able to drive it up the ramp into the workshop with no problems at all...