2000 explorer is dying while I drive. It will start back up but with some difficulty. Could it be the fuel pump? The gauges do flicker a little but doesnt seem like the alternator. I drove 300 miles yesterday and it only died a couple times on the freeway and was able to restart it. Its having a little trouble starting now.

Have a fuel test done on it, that will tell if the fuel pump is weak, or the fuel pressure regulator is malfunctioning. When was the fuel filter changed last?
If the fuel test doesn't show anything, further testing would be recomended.

Which gauge flickers. When last did u changed your fuel filter I usually changed it every 6 months and they are not very expensive. ONce your fuel filter is dirty eventually some debris will come out of the filter then it will go to your injectors and that is not good.

Ok Brother, Seen this before, the issue I think is something in the belt drive is going bad, Remove the fan belt and try to turn every pully by hand, except the crank shaft. The one that doesn't turn is the culprit.