My husband and I bought a used 2010 Hyundai Santa Fe that I like very much. However it has a serious and frightening problem. When driving in the rain, the steering wheel begins to jerk rapidly back and forth. The steering is responsive and smooth at all other times. We did not notice the problem immediately because we have had such a bad drought here that it has not rained much since we have owned the car. In fact, we had owned the car 3 months before we first encountered the problem. We took it to the dealer and they could find nothing wrong, but it wasn’t raining. We returned to the service department on a rare day when it was actually raining and still the dealer could find nothing wrong. It seems that uneven or bumpy pavement makes it worse. The tires were in good shape when we got the car and are now getting to the point of needing to be replaced but we can’t keep the car as we feel it is unsafe in the rain. Any ideas on a suitable next step?