weird fuel problem, ('96 XJ)

I have a 1996 XJ Sport 4.0HO 5speed and it has a weird problem.

I recently got it and when I got it from the previous owner he said on long distances the fuel pump would act up but if you add gas it would be ok.

I have owned it for 3 weeks without a problem beating around town and out on trails. Never took it farther then I would say 60miles. Put 300+ miles on it without a problem.

I trailored a car 200 miles on way last night without a problem. On the way home this morning 100 miles outside of my destination The car just sputtered out and died rolling down the high way. I pulled over and and just let it cool down. Started it back up and it sputtered and died out. Waited alittle bit more time then it sputtered again gave it some gas and it cleared out enough for me to make it to a gas station 5/10ths of a mile up the road. Pull into the gas station and it dies again.

Add $10 in gas start it up immediately and drive the rest of the way home. Keep in mind I already had 3/4's of a tank before I added $10. Get off the highway and take my co-pilot home and it dies again? Add $5 more and drives home without a problem.

If it was the fuel pump, it would either work or not work right?

What would cause this to happen only on long trips and not just beating around town?

any help would be greatly appreciated as this is my DD.

Intermittant running is usually the CKP crank position sensor. Try splashing it with cold water when it stops running. Often they go bad in a heat sensitive manner. Other direction is to check fuel pressure with a gage on the fuel rail when it won't run. Or try spray start when it won't run. Sometimes a hose inside the tank comes loose, but it's hard to see how that could cause these symptoms. You need to know for sure if it's a no gas situation with a fuel pressure gage on the rail.