Need Diagnosis..., Front end suspension area is vibrating while driving.. Options

[Betta-J]

So, lately I've noticed that on the highway my front area of the car vibrates. I am sure it's between the two front tires or at those locations b/c it vibrates up there. It's very sporadic and I can't tell when it will happen again. I have checked my tie rods (don't know if I can tell if they are broke or not, but physical damages or cracks I can't see), I don't think it's my wheel bearings, and my stabilzer bar looks to be in tact. I have also checked my CV rods/CV boots and don't see any physical damage (again, don't know for sure). I took my wheels off and put them back on to see if I didn't tighten them or something. I can't find anything wrong.

These are the times it starts up:
-when decelerating from 70mph (just letting go of the pedal)
-when I'm going down hills on the highway (I had cruise control on, but it's like the above--maintains speed)
-when I accelerate quickly from 70-75/80mph
-at higher speeds (at 5th gear)

Any help would be appreciated. If you can PM me that would be great too.

Is this a symptom that Celica's have? I figured the 99 wouldn't have any problems. (if anyone knows a site that lists all of the known things that go wrong with the 6GC, I would appreciate that too)

Thanks.

[Fastbird]

Get the car on a lift and see if there's any tie rod or ball joint play. If no, check the tires, see if the treat is separating. If none of the above, do a tire rotation and get them rebalanced (as they wear the balance slowly goes out). If that doesn't cure it, go get an alignment. It's a often neglected maintenance item and will make a world of difference with just a tenth or two degree out on the toe in.