PE99066, INTERMITTLEY WHILE DRIVING, THE STEERING WHEEL LOCKS UP, CAUSING A LOSS OF STEERING CONTROL AND A CRASH. CHEVROLET SAID IN ORDER TO UNLOCK THE STEERING WHEEL HAD TO REMOVE THE KEY AND WAIT 20 SECONDS. DEALER REPLACED PARTS IN THE STEERING SYSTEM, BUT PROBLEM IS REOCCURRING. DEALER CANNOT DETERMINE THE PROBLEM. PLEASE PROVIDE FURTHER INFORMATION.*AK REF. IN EA02-031 *CJS