Intermittent shaking at all speeds

[HMPower]

My Vibe started having this issue a couple weeks ago. I'll be drivign along, and suddenly the wheel will start to shimmy in my hands, feeling like an out of balance wheel. It will increase in intensity within a couple miles to the "I should probably pull over" stage, and then it will just go away on its own. Sometimes this will happen a couple times during the same drive, or it will go several days with no issue.
I had the front struts replaced about 2 years ago, the ball joints seem okay, and there's no obvious alignment issues. Any ideas on what this could be?

[sideshowalan]

In what speed-range does this happen?
Any reason to believe it's not an out of balance wheel?

[HMPower]

It will happen at any speed. Usually it begins at highway speeds, and will continue all the way down to a stop. The weird part is the intermittent nature of it. It feels just like an out of balance wheel - when it started I thought a wheel weight had come off, it was so sudden - but I've never had a wheel balance issue that came and went like that.

[GOF]

Any sounds with this? It almost sounds like a wheel bearing. Heats up at highway speed causing the vibration.

[gtv237]

Sounds like a CV axle to me. I had one so bad once that you'd be going down the highway and everything would be fine then out of nowhere it would shake like crazy and you felt like you were losing all control and then it would be fine again the next second.

[sideshowalan]

Could be a lot of different things, you're going to have to play around with it.
With the front end in the air, grab and shake each of these things, feeling for play/movement.
-Outer Tie Rod ends
-Sway Bar LInks
-Ball Joint (lift up on the wheel while you have one hand on the joint)
-CV Axle
-Strut Mount

If it's that bad, one of these things is bound to be worn.

Wild Cards:
Sticky brake caliper - Does one wheel feel unusually hot after a drive?
Internal tire tread failure - rotate tires and see if the vibration moves to back end.

Whatever it ends up being, let us know. Good Luck.