SW2 runs rough

I have a 96 saturn sw2. I start it and tap the gas in neutral and it boggs down and dies. then when i start it back up it spews white smoke for a couple seconds. If i drive down a highway and come to a stop sign it boggs out and stalls. please help

its got 184,000

update: aparently the guy i bought it from had taken out the thermostat for some unknown reason. so i replaced that and it works perfectly now.