I'm having a very similar problem. It was only jerking at high RPMs with low fuel. Now, after a 400 drive across California it's completely dying on me. Half tank, full tank - it's all the same; stalls at over 50 all the same I think it's time to replace the fuel pump, but it costs a bunch if you don't do it yourself. It should be doable [except for getting that metal ring off] for about a $100 [cost of new pump @ kragen].

Contour '97GL 2L ATX, ~100k Pioneer sound system A few unintentional scratches on the back and a rebuilt tranny