make sure everything is tight. ball joints, sector shaft, intermediate shaft, i also have had issues with pilot bearing and most recently found my tcase separating from trans and had some vibes. pinion bearings can be hard to pinpoint as well. if have a rack put it in the air in drive and listen for vibes with screwdriver or fancy doctor thingy. or for laughs go take it into a shop for their free inspections? see what parts they want you to throw at it.
just jiggle the keys in the door.