Nissan Repair: Nissan Runs Rough, blown head gasket, half tank

Question
I have a nissan with 1993 220,000 miles on it that I am trying to fix for my nephew.He let sit idle until it ran out of fuel.He says he did not have even a half tank but a quarter he guess near it.anyways,I have gotten a new radiator in and change the antifreeze.It was cooked white nothing else in it.The oil was black changed it and it did not seem milky or anything.White smoke was coming out exhaust but that was months ago and I just decided to mess with it again.it cranks fine but still runs rough but the white smoke is gone or either burned off.does this sound like a gasket problem or maybe something else got damage.The car is not even overheating from what i can tell that is why I am asking.any help is appreciated. Thanks

Answer
Bob,

You either have a blown head gasket or a crackeed head.  I would think a blown head gasket.  I would suggest you do the test to see if you have carbon dioxide in the radiator.  There is a kit to buy with a liquid and a bellows that you pull the air from the radiator through and if the yellow fluid turns blue the antifreeze has exhaust in it.  If that is the case remove the head and inspect it and the head gasket.