One problem related to front suspension wheel bearing has been reported for the 1999 Hyundai Sonata. The most recently reported issues are listed below.
Noise like a helicopter is in the back seat,to dealer and wheel bearing are gone,parts unavaiable the second time(02/01) sec to backorder,same problem again 02/02)check engine light on sec to a cam sensor,sesor replaced, at 70mph lite come on and car stalls next is airbag light come on after seat is adjusted(driver) have never had to test them so can only hope that whe n car stalls they will deploy.