1987 Chevy Camaro have trouble starting

When the problem occurs, your saying it cranks good but won't start? If it has been a while, I'd give it a tune-up. With extended crank, have a helper crank it, while you visually check for spark at the plugs. If you have spark everywhere, use a gage and check fuel pressure. Even if the fuel pump is good, if there is something wrong with the wiring circuit, the pump won't run. If the pump gets voltage from the oil pressure switch, instead of the relay, that can cause an extended crank. Any applicable trouble codes.