whats up fellas hoping you can give me some insight on my 07 g35x

i know the fuel injector in bank 1 is bad since i got the car a week ago and the dealer said theyre fixing it this week but my concern is when i go from park to reverse or neutral to drive the rpms go to about 1100 (in park and neutral) and then drop when put in reverse or drive but i feel the jerk when it engages. it shifts fine when driving just again a lil jerk when it downshifts into 2nd or first not sure exactly which one but my question is would a bad fuel injector which is causing a misfire in cylinder 1 cause this jerk into gear and down shift or is it my mounts?
Or do i have to wait for them to swap the injector to find out?
and if it is the mounts how hard are they to swap on the a/t?
im pretty mechanically inclined just curious on location, cost, and if its difficult to diy
thanks