Accord shakes when idle with AC on (replace, motor, used)

[lifeexplorer]

My Accord is over 12 years old now. Recently it develops a problem. It shakes when idle with AC on. It comes in waves of every 2-3 seconds but once I turn off AC, there's no problem.

Any idea what could be the problem or even it is a problem that I need to be concerned with?

[jaypee]

I don't know if it relates to your issue but I used to have an Accord of that vintage and I had to replace the motor mounts because of the shakes (I don't recall it being related to the AC).