2003 Ford Focus car shakes

The AC adds additional load to the engine so some vibration is expected. Check your belt tension and operation and the quality of your motor mounts. Fatigued motor mounts will not absorb as much engine vibration.

thanks. But I just changed the motor mounts. serpentine belt is fairly new. belt tensioner is new. high speed relay is new, for the A. C. fans. Could there be some another problem? anything that will help me, will be appreciated.

It could be the IAC isn't correcting the idle sufficiently or it could just be normal from the increased load.

thank you. the problem was the passenger motor mount and the transmission mount. Gracias.