Bad Fuel pump, clogged fuel filter or something else?

[EvinH]

Need some help in diagnosing a weird problem with my newly purchased used ST. On my drive home after purchasing it, when I came to a stop and made a turn to go up a hill, the motor lost power. Not a complete shut down or loss of electric power, but it just would not respond to throttle input. Prior to this I had been cruising at about 45mph for a few miles on a hilly, winding road with no problems. When the issue hit, the RPMs dropped slowly, as did my speed. Throttle input, even matting it to the floor, had no affect. I pulled to the side of the road and the motor was stumbling and bucking, then it settled down and I was able to continue on. About 10 minutes later, same issue happened. The ST slowed to a crawl. I let it sit for a minute or two, motor running and in drive, I was able to drive off again and get up to speed, but throttle input seemed non-existent again, although I was able to get back up to 40mph. When driving, everything felt fine, no bad vibrations or funny noises. Oil pressure looked good, battery volts looked good. It seems like the computer put itself into limp mode or something. I haven't put a scanner on it yet, but will. Wanted to get some ideas of where to look. All the fuses look good, again, it didn't lose electrical power, it just seemed it was not responding to throttle input at times.

This is a 2001 ST with the 4.0L V6, it has a 114K+ miles on it. The gas tank and battery were replaced about a month or two ago. Not sure if the fuel filter and/or fuel pump were swapped at that time, but the previous owner said he drove it a few hundred mile w/o problems. So just looking for ideas as to where to start looking. Thanks!