2001 Dodge Caravan Fuel Pump issues

I have had this 2001 Grand Caravan for over a year now. It bogged down one day last year, went to skipping (got a misfire code) and simply wouldn't run. Our mechanic found the fuel pump to be bad, replaced it and it ran good for a couple of months. All of a sudden, it came down with the same symptons, and code, he said the pump was bad and replaced it under warranty. Well, this just happened again (3 new pumps total). The common situation in all of these times is that the fuel guage has been on 5/8 of a tank everytime, you can get it towed to a gas station, top it off and it will skip a minute or so, then run like a top from that point on. As long as you keep it over 3/4 to full it runs flawless. Any ideas?