I have a 92 Bonneville SE, 93 Bonneville SE, and a 97 LeSabre.
I had a similar problem with my Buick and my 93 Bonneville.
It turned out to be a bad ignition coil on the Buick and a bad ignition control module on the Bonneville.
Use a spark tester (available at any parts store) to check for proper spark at each coil.
It should be 25,000 to 40,000 volts. If you are not getting proper spark from one of the coils replace it. If you are still not getting proper spark with the new coil, odds are it'* the Ignition Module.
Hope this helps.