Wires are just one years old, same as the plug. They have about 20k miles on them. I ruled out the wires because I haven't experience missfiring.
I've also pulled the MAF and IAC electrical connector today, but neither stalled the car out... When I pulled the MAF, nothing weird seened to happen; and when I pulled the IAC, the car stalled the first time but the next time, it only have rough idle.