Need help with a problem on my 2000 Monte Carlo LS
 

I own a 2000 Monte Carlo LS when I am driving at times my car will feel like it's jerking also omw home it shut of on me it started right back up until I put it in drive and pressed the gas then it cut off. For it to run I had to put it in neutral and give it gas then in drive. Can anyone help me find the problem?