1996 Mitsubishi Eclipse could it be my fuel pump?

In my mitsubishi eclipse, I have ran into some major problems recently. While driving a couple of times, the car would just slow down. While pressing on the gas petal to speed back up, all you got was the car slowing down more. Then it would stall out. It would eventually restart after long periods of time. Now that the car has not been used for months, it is sitting in the garage. I am trying to figure out what's wrong with it. It will now start and idle for about 45 minutes then when it gets shut off and you restart it, it will die. My fuel pump was replaced a year ago. We thought it was the coil pack but that was fine. The check engine light hasn't popped back on so when hooked up to a computer, it doens't pull a code. I am at a loss of what this could be! Could it in fact be the fuel pump again? Thank you!