If put new spark plugs n coil packs do you think it would start
is the engine cranking over and getting fuel?
If it is not starting now, I doubt that changing the plugs will make any difference. Also it has 3 coils packs and it is unlikely that all of them are bad. If one coil pack was bad I would think that it would start, but run really rough. You need to determine if it is getting fuel to the injectors and if it is getting spark to the spark plugs. Only then will you be able to figure out what is wrong. Don't just start throwing parts at it.
Search Buick Riviera Questions
Buick Riviera Experts
Related Models For Sale
Used Cars For Sale