I know nothing about cars and I would like some advise if my problem is simlar to the ones mentioned above.

I have a 2000 Ford Contour SE with 40k miles on it. I recently went to Tennessee from Cincinnati Ohio and it stalled and lurched forward when climbing the mountains. I had difficulty keeping it at 60mph. I had 1/2 a tank of gas. When I returned home I had a full tank and it did not have any problems even though I drove over the same mountains.

when ever I go up a steep grade with less than a half a tank it lurches. Could this be a problem like those above, and can anyone tell me an approximate cost for fixing this problem.