2000 G20(same as Sentra) starting problems

I?ve got a 2000 Infiniti G20 same engine as a Sentra, just the other day i tried to start the car and it turns over and fires up but immediately just goes dead after, I can push down on the accelerator after starting to rev up the rpm but soon as i let go the engine just goes dead again, not sure if i?m damaging the vehicle more when i do that cause a thin cloud of smoke comes from the engine when i rev it up. i?ve had issues with my thermostat in the past, but dont know if that would be a reason for this issue. I?ve got 150k on the car, and no major accidents in the past. If anyone can help it would be enormously appreciated.