When the engine is completely warmed up, and is at idle, the throttle % should be at zero. If it is, its all good. Mine will sit at zero and bounce up for a split second to 1% I dont know what is up with that but seems to run fine. Of course mine runs like crap if I try to set the idle (with the idle speed adj.) to within spec. I have to let it idle at about 1100~1300 rpms. If I dont, when I ride it and let off the throttle, It wants to die.
I wouldn't think you would need a new map due to a spark plug change. Dosen't really change the air/fuel ratio.