strange steering vibrations

Ive recently noticed the front end up my 2006 tacoma 2wd prerunner access cab has been making weird vibrations. It almost feels like my truck is bouncing and it only happens when im in between the speeds of 20-50 mph.
So since then ive replaced my inner/outer tie rods rebalance d my wheels and also replaced my upper and lower ball joints. Also took it to the toyota dealership and they said my truck seemed to be fine. Long story short my problem is still here.....anybody have a clue what I can do

 

Check driveshaft u-joints and center bearing are tight.

 

Ill give that a shot hopefully that solves my problem thanks !

 

Rotate your tires and see if the 'vibration' changes.

Check & Lubricate your driveshafts/ujoints.

Check your driveshaft to make sure none of the balancing weights fell off.

Check your Ubolts on your rear suspension and check your pinion angle.

 

I had something similar.

It went away after an oil change where they also cleaned up the brake calliper sliders (and whatever else they do as part of that routine service).

Eventually it came back again (8 weeks or so). Sometimes quite badly.
I just lived with it and each time I went in for an oil change/service, it went away.

It has now been 8 months and it hasn't come back.

NOTE: The symptoms happened at highway speeds just driving. it got worse and shuddered under hard braking. It wasn't the rotor. I have never had them turned or replaced. Maybe it was just cleaning them? Whatever it was it was mysterious and is now gone.

 

Ill try to do what everyone said id just like to figure it out thanks everybody!