The intermediate steering shafts in 1984 Corvettes are notorious for wearing out and causing slippage as you make turns. The shaft is constructed of two pieces mated together with a spline. The spline wears out and slips.
GM no longer sells these shafts so you have to get it repaired or find a re-built one. Nylon or metal bushings are inserted around drift pins where the two sections of the shaft are joined together