1999 Lexus ES 300 My engine sputters and turns off once or

Hi I have a problem with my car. Out of ten starts about 2 to 3 perhaps even four times it would spudder and turn off. I asked someone and they said it could be the sensor. So I sprayed and cleaned the sensor but it still does the same thing. I turn the ignition and I hear the engine start. Then sometimes it would go up to 2 on the thing where when u press on the gas it has numbers from 1 to like 9 or something. Sometimes it would go to 2 and drop down to zero and the engine would shut off. It won't idle right sometimes. Normally it would stay at number 1 and everything would be fine. This would happen 1 out of 4 times I start the engine. What could this be? It's not the starter because it does start. Just sometimes it would spudder and shut off. Please advise