Pontiac Grand Am 1998

I have a 1998 Pontiac Grand Am GT 6-cylinder. A few weeks ago as I was driving it began to lose power and sputter. It quickly fixed itself and I went on. When it did it again I thought that Water may have gotten into the fuel so I fueled up at a different gas station and it seemed to fix the problem for a few days. Then it went back to doing the sputtering. It has gotten worse but it seems totally random (This morning drove fine, but when I was driving home it sputtered and lost power)
It has begun to sputter and die more frequently, and even backfires now. Here are the talking points.
1. It starts up fine and will idle fine.
2. Goes in Reverse fine.
3. Will begin to sputter and lose power randomly and will begin to backfire if you press on the gas.
4. Had Catalytic converter checked and OK.
5. Disconnected the TPS (throttle position sensor) and it still lost power and sputtered like about to run out of gas.
6. Here today it had a bad spell and I almost didn’t make it home. Let the car sit for about 10 minutes and started it back up and it ran fine.

Opinions and Suggestions?
Thank you,