2000 ford focus

My focus would not start, I replaced the fuel pump and filter and it started. I drove it about 10 miles. The next morning it stared I drove it a few miles and it quit, I started it again , went about 300 feet and quit and it kept doing this. I then replaced the fuel pump driver module located under the back seat, this still did not fix the problem, it starts fine and runs at a idol if I try to give it gas it wants to quit. what could be wrong with it now ?