A fuel delivery problem of some sort seems most probable. Pump is certainly suspect here especially if it's been loud. I agree with recommendation for testing. Put a fuel pressure gauge on the schrader valve on the fuel rail. If you don't own this equipment, you can rent from many of the bigger parts store. Compare to spec. Change fuel filter if not already done so. Good luck and post back what you find!
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!