about 20,000 km's I did my tune up according to Honda's maintenance schedule and my driver-side motor mount was gone, and the car jerked vigorously whenever the car shifts gears(auto). I replaced it with an OEM mount and the car was fine after that, but now the jerking comes and goes from time to time. I'm not sure what the problem is I was thinking it may be the driverside motor mount again but is there anyway to find out?

And is it hard to replace the other 3 motor mounts? the driverside was easy

 

Just get some HASport OEM mounts