1990 Chevy 1500 305 5.0 engine

I don't know what testing you have done? Make sure battery has a full charge. When problem is ongoing, have a helper crank it while you visually check for spark at the plugs. If spark everywhere, check for proper fuel pressure and fuel injector pulse. If the engine is hot, wear gloves. Any applicable trouble codes? Your obd1 so if your check engine lamp works, you should be able to check some codes, yourself. You use a jumper wire at the A & B terminals at the aldl. Turn key just until dash lights come on, then the mil on the dash starts flashing, you count the flashes to get the codes. Your looking for two digit codes.