1989 Oldsmobile 98 won't start

If you have good spark and fuel pressure when it doesn't start, you need to check if the injectors are getting power. You need a noid light to do this. Unplug an injector and crank the engine. The light should pulse when it gets power. An easier way is to just see if it will start with starting fluid. If it does, then no fuel is getting to the engine. If it doesn't, then chances are you are not getting spark. Make sure that both fuel pressure and spark are there when it doesn't start so you know what area to work with.