Why my car do not start? on 1991 Buick LeSabre

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.

Asked by for the 1991 Buick LeSabre
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