I have an on-and-off vibration through the steering wheel on my 03 Outback (2.5L automatic). Comes and goes with no rhyme or reason for days at a time. It occurs only when I am pressing the accelerator and disappears when coasting. With it is a loud tapping noise when I turn right and am pressing the accelerator. I have been told the C-V joints are fine. Recently had bearings replaced on the left front.
I’m not sure how the CV joints were checked and said to be fine, but that is a lot like and inner CV joint problem. There isn’t really some kind of check of the CV joints that can eliminate them as a problem. I think that is the most likely culprit.
Though - there are other possibilities. You might have a problem with the right front bearings - if the left just went then the right might not be far behind.
Someone should also carefully inspect the motor and transmission mounts.