This just does not sound like a crankshaft issue to me. I'm thinking that it may be a fuel supply issue since it doesn't seem to have enough oomph to run, but will try to crank. Have you tested the fuel pressure? What about fuel filter replacement?

 

ok heres the update...bad battery to start..only 6 months old...new one put in and alt. is fine tested...starts and runs fine but sounds like something is rattling around inside either the exhaust or maybe oil pan??? i dont know exactly where... when i start it though it make a big bang/rattle when it first starts but once its started it seems perfect... could there be something floating around in the oil and cause that loud noise when i start it? maybe warped crank??? but if that was the case you would not think it would run so well after start...

 

maybe broken starter tooth???? whatta ya think ...maybe thats causing the gringing sound when starting?