Why my car do not start? on 1991 Buick LeSabre

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
I've tested the starter and the alternator out at the mechanic shop, but they said that it's working fine. I also changed the battery and still my car don't start.
(2) Answers
bad coil packs or modulator under coil pack
Check the ignition switch as this car is old enough to have worn it out