What causes the steering wheel to shake while going at high speeds on the highway? Also, it shakes when the highway curves to the right or left…what would cause this type of problem?
Worn tie rod ends or loose wheel bearings. Jack up each front wheel, grab the tire at 9 and 3 O’clock position and try to move it back and forth. Then grab it at 12 and 6 O’clock postions. If you get some movement, have someone else do the same when you’re under the front wheel looking for where the play is. It could be the hub bearing, tie rod (or rack and pinion mount/rod) wear, it could even be worn strut bushing, ball joints, or tires with internally separated belts. My money is on the tie rod ends.
I will add damaged tyres (may have internal damage not visible from the outside) and out of balance wheels/tyres.
If a tyre is damaged internally, it is a serious safety hazard.