I have a 2007 Ford Escape 2wd 4cyl with around 170k miles on it.

Recently it has been "drifing" in the lane without any steering input.  It feels like driving on a day with strong gusts of wind that move the car sideways slightly and changes the direction by a few degrees requiring steering input to stay in the lane.  The steering does not feel loose as just small inputs will usually keep me in the lane.

Less than a year ago I replaced the front lower control arms, front upper control arms and sway bar links.

I just took it in for an alignment and they didn't mention anything that needed replacement other than some aftermarket items to get the camber back in to spec on the Left Front and Right Rear wheels.

Could this be an indication of worn wheel bearings?  There is no noise or perceptible "bump" when the change in direction happens, so I don't think anything is loose in the steering system.

Any help or suggestions would be greatly appreciated as I really don't want to take it to a shop and have them gouge me on a bunch of stuff I don't need.

Thanks!

UPDATE: last night I put the car up on jack stands and took the wheels off.  There is no play in any of the steering components at all.  What I did find was that the rubber bushings in the rear contact point of the lower control arms were torn in multiple places on both the driver side and passenger side control arms.  I just replaced these less than two years ago.  Play in this area would explain the lack of noise when the lower control arms shift under pressure resulting in a steering angle change.  

Question: does anyone know why these would fail so quickly?  I don't abuse the  car or take it off road at all.  When I replaced the control arms, I also replaced the tie rod ends and sway bar links.

Lift up front of vehicle. Make sure steering wheel is unlocked. Grab front tires at 3 and 9 and wiggle side to side for play. Then wiggle up and down at 12 and 6. I don't expect to see a wheel bearing being your problem.

do you feel play in the steering when that happens?
do you have to turn before the steering starts to change direction?

alignment people may or may not have time to check for worn parts.
They only care when it prevents them from getting the alignment done.
for instance I ran into one case where the entire rack was loose. IT shifted as you turned the wheel.
I think it went through 3 techs before I caught it and fixed it.
Car would randomly steer in another direction. turning the wheel would take almost a half turn before the steering changed because the rack shifted first.
you couldn't see it on the lift because it was hanging and had no resistance. turning the wheel like that didn't move the rack.

I prefer the dry park check over the 3 and 9 position. Leave car on ground, unlock steering wheel, engine off, rock steering wheel side to side and check for play in steering linkage. You will have to have someone rocking the steering wheel while you check. You still need to jack up the front end to check up and down.

Andrewh, no I don't feel any play, as in a change in resistance to turning the wheel.  However I did try and turn the wheel slowly from side to side, and it appears that there is some play where a change in the wheel does not create a change in direction.

Tonight I will have my son rock the wheel back and forth with the engine off while I try and find any play in the linkages.

Thanks everyone for your suggestions!

Bump for edit in op.

Thanks for everyone's help here.  I really appreciate it.

some items have to be assembled loose then when the car is put on the ground, tightened.
If you tighten it in the air, it binds the rubber and it will twist when it sits on the ground accelerating the wear.

OR, just cheap parts that went bad early.
Mostly I used to buy moog, till the went to china. But if they are moog, they are lifetime parts, and you can see if they will replace them for free.