A little Help with my car trouble!?

I have a 2002 Toyota Sienna. 6cyl. has approx 142,000 miles on it. recently paid car off now it has a problem. It starts Fine but will not go until you give it gas. I have been driving it and when it dies it starts back up again. I know its not the starter,battery, or alternator because everything is on lights,radio,etc. It does have gas and when it runs there is no check engine light on. has any one have any idea what it could be.