One problem related to engine has been reported for the 1996 Buick Riviera. The most recently reported issues are listed below.
Electrical (?)--the engine dies while driving at highway speeds. The engine will not restart when shifted to neutral while still rolling but does restart when the brake is applied! this has happened seven times during the past 9 months and is happening with more frequency--4 times this month! the Buick service dept. Has not been able to recreate the problem and cannot determine the source of the problem.