i have the same problem. i just bought a 2006 xb with 94kmiles and its automatic. my car vibrates a lot when its in D or R only when on full stop. so i went ahead and change the spark plugs with ngk platinum (2.49 ea). still vibrating, changed my air intake to a ebay CAI thinking it might be the air intake that was causing it since it was the only one shaking crazy under the hood. but that didnt do it though however. so i took it in to the dealership and they replaced my motor mounts.. less vibration now however, when a/c is on, starts to vibrate heavily again and can hear rattling noise when in R. so they r gonna do another diagnostic on my box.. ill find out tomorrow hopefully! i hope she's ok. i hope whatever she has is treatable.. lmao.. what do you guys think my box's prblem??