RX330 2006 Vibration when put into gear.

[JERr]

My 2006RX 330 vibrates when it it put into gear.  When put into park, neutral or with acceleration it goes away.  I had the front and front passenger side motor mounts replaced.  The other mounts I was told are ok.  Also told the catalytic converters are bad.  Dont know if that could be related.  Plugs and coils were replaced.  Otherwise the car runs really well.  

[RX400h]

Perhaps if the catalytic converter is partially plugged and producing excessive back pressure, the idle will drop. This could be the problem. A test would be to disconnect the catalytic converter and then see if the vibration goes away.

[JERr]

I'll look into that.  Thanks