1995 legend intermittent vibration under power

i am experiencing a front end vibration only while under power … it stops when my foot is taken of the gas. sometines i don’t feel it it gets much worse as the car warms up sometimes it gets so bad tah i feel the car shifting from side to side like the engine is moving from side to side i have had several mechanics look at this some have said they think it is transmission sone say a combination of issues with front end. I have replaced both complete front wheel bearing assemblies

There are many other front end worries other than just the wheel bearings. Here are a few: Motor mounts, tie rod ends, ball joints, struts, and bushings. This is a 13 year old car, and any of these are suspect, and can cause the vibration. Also, when was the last tune-up?