so as the title states, can a bad therostat be the problem? or is it what i think it is....

 

its prolly what u think it is. it could have started as a bad thermostat. the sputtering is prolly from running hot and the fuel evaporating before it can ignite.

 

the white smoke is what engine coolant looks like after it goes threw the engine

 

those are all symptoms of a blown head gasket.

 

I had that happen to me ended up being a blown head .Does your oil cap look like it has coffee w/cream looking liquid in it ,if so blown head

 

It all depends where the gasket blew. if oil is getting into the coolant the radiator will have a nasty milky looking **** in it. if the coolant is getting into the oil the oil cap and dip stick will show signs of the milky ****. if its leaking inbetween the cylinders u will just get white smoke out the tail pipe

 

you blew the head gasket.