1997 Saturn SW2 only starts once

My Saturn will start the first time after sitting for a long with no trouble and idle fine. If I tap the gas it will sputter and will almost die out but usually recovers. When it does start the first time a burst of white smoke comes out of the exhaust but I am not losing coolant so I dont think it is the head gasket. If I shut the car off, it will crank over just fine but it will the engine will not start. So far I have done a spark test and the fuel pressure checks out normal, I have replaced the fuel regulator and filter, coil packs, plugs, and wires, throttle position sensor, and crank shaft position sensor. I am unsure what to do next? Please help!