Car not starting

An engine that had no coolant in it but was continually driven may have experienced severe internal engine concerns causing damage that is not resolvable without tear down and replacement or repairs. All the guessing games you've done to attempt repairs don't seem to have resulted in anything positive or worth the money invested. I'd perhaps pull spark plugs and inspect condition and see if you can tell anything from that. I would crank the engine manually with a breaker bar and socket on the crankshaft to see if it even turns freely. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops