2001 Chevy Venture Hard Jerking and Hesitating

I have a 2001 Venture. Just recently while driving at around 50mph and up it will start to jerk really hard every couple of seconds and hesite. If I push the acellerator it feels like it isn't getting any fuel. Just hesitates and jerks. If I slow down to below 50mph or so it will be fine. Also it doesn't do this while driving in the city. Only at higher speeds on the freeway.