Engine shutting off while driving
 

Problem started recently the truck would drive fine and out of no where it would shut off and all the warning lights would go on. But when you pull over engine would restart fine. A few days ago all the warning lights came onn but the truck kept running fine until i came to a stop sign then it **** off. Could it be the fuel pump going bad or the relay i cecked the fuses and they are fine. Never had much trouble with my truck
2003 expedition xlt 5.4l 4x4 140k miles
Spark plugs and coil packs changed 4k miles ago with Motorcraft parts
Fuel filter changed 15k miles with a Motorcraft filter
All other scheduled maintenance was done

Welcome to the site.

At 140k fuel delivery certainly shouldn't be ruled out, but the instrument panel warnings generally won't illuminate with a running engine if pump related without a stall. A lot of times on a failing pump, the re start isn't always instantaneous.
So never any CEL?
Could be a cluster/PCM, communication issue etc, Could be the pump relay is losing it controlled grounding from the PCM and the pump run stops. At any times after the stall, do you have a no start? If so, cycle the key to ON and listen for the timed pump run.

After the stall, the engine cranking speed seems normal?

No check engine light never had any electrical problems with the truck. The problem usually starts after 20 minutes of driving. Could it be something totally unrelated like a bad MAF or idle control it has been a while since i cleaned those. Also my battery seems a little weak dont know if that could contribute to any of the problems.

A healthy charging system is paramount, although if the rate of charge is out of spec, the warning indication should be there. Generally, the truck would run until the system voltage dropped off and a stall occurs. If it cranks fast enough to start, there should be enough current for the system for a run, or at least for a while. But sometimes it's good practice to look at what's not the problem first ( rate of charge- spec fuel pressure/volume) before moving forward in a diagnosis or just assuming.
If the stall is very predicatable meaning time/ miles, and battery or charge may be questionable, I'd have a look there first to prove it out..

I have to look at it this weekend but my wifes uncle thts. Machanic is hell bent that the pump is bad

For what it's worth, There have been some problems with the power relay in the Central junction Box which gets it's power from the ign switch. That power relay also controls the F/P relay within the smart junction box, which by the way, is not serviceable.
I believe Hayapower is steering you in the right direction with something dropping out.
Instead of jumping the gun and possibly replacing a good fuel pump, why not tap into the line supplying the inertia switch and watch for a power loss when the engine quits. That power supply goes to the fuel pump. You would be reasonably sure if the power stays on to the pump and it's ground is good that you have a pump problem. If on the other hand power drops out , you could wind up replacing a good fuel pump.