I would guess 320 miles.
Believe me when I tell you this story, I replaced mine a while ago (April 05) and it got real cold here in Texas and I was at a mall the day before Christmas (2008) and I went in for an hour came back out and the Explorer would start and quit, like it was out of fuel.
I knew it was the fuel pump because the electronic pump was silent.
I thought to myself, SOB, because it was a pain in the you know what, to drop that tank and remove that entire assembly. (even though new fuel pump has a life-time warranty.)
I do not know what possessed me to lie on my back in the parking lot and smack the bottom of the cage below the tank, but I did.
Went back to the Explorer, and it started right up.....
No problems yet....
Anyone out there knows what might have happened and has it ever happened to you....?
d-1