2000 ford excursion 5.4. Multi issues.

Hey guys. Thanks for your time. Most of yall know me and most of yall know I dont post unless im really stumped.
Iv got a 2000 ford excursion xlt with the 5.4 Triton with around 215k.

I just dropped over 1000k into this truck. But that is ok I got it for a steal.

Here is the deal.

The truck has set for sometime. 2 plus years.
When I first started the truck – it ran really rough. After a tune up it did get alote better but still had a slight roughness when reving the engine. -This was also present before the tune up.
I recently started doing repairs to the truck to get it road ready again.
Here is a list of things i have changed.
New brake system. Master Cylinder and calipers – break pads.
Plugs – and boots.
Plenum gasket.
Air idle control.
Oil change.
Fuel filter.
Fuel tank was drained some time ago. Fresh fuel.
When I changed my plenum gaskets I soaked the injectors in diesel fuel. For around a hour or so…. I also used the spry seafoam and shot it threw the throttle body housing with it running..

Ok the first problem I noticed.
When I first got the truck running again – It had a slight hesitation/missfire when revving the truck – as it ran it got better but never fully went away *I figured it was from setting*. The more it ran the better it did seem until yesterday.

The 2nd issue I have noticed. When you put the key to the run position. The truck will not allow any power to electric system (Windows/locks/ stuff like that) It takes almost a min of the key being on and then you here the truck DING DING DING and the power will come on allowing you to use the windows and stuff. Then some time later the truck loses its power again and will not come back with out restarting the truck or turning it off and back to run *Does this running or with the key in run position and engine off or in accl*

Now yesterday – I did the title and tags and insurance. 300$+…. *This is the first time Iv seen it do this
When I first started the truck to pull it out of the shop and put the new plates on it acted fine.
Then on the 2nd start (5 mins later) It wanted to idle high.@ 1500rpms When I gave it gas it wanted to stay at 2000rpm.

(I checked lines and did not see any lose)* NOTE *(After the tune up – I started it everyday for almost 2 weaks and let it run for 30 mins or so)
So I Thought maybe junk got in the AIC and a nice run would help it. The Rpms did finally drop.
Took her to a station put some fuel in her and took off.
It did have a slight misfire when taking off. It seemed to get better for a min but then started noticing delayed shifting……. About 3 miles from the station doing about 70 I noticed a lack of power—- Figured it was from setting and it may clean its self up… Nope got worse – to the point wear any thing more then 1/4 throttle and it would try and die or lose almost all power.
The shifting did get better.
To me it acted like it was losing fuel.
Here is wear it gets weird. There are no check engine lights on.
After driving so long the truck will finally just lose all ability to accelerate and will fight to maintain current rpm/speed. If you pull over and put it in PARK the truck will still not rev what so ever.
If you shut it down she will fire right up and you can rev it all you want. until you take off again *It still has a slight misfire or hesitation* – Once you try to take off it will drive semi ok for maybe 1/2 mile and start losing power again. It slowly loses power *Not all at once* The more you try to drive the worse it gets. To the point you have to pull over and restart.

Im currently at a loss for this. I kept thinking fuel pump but why does the issue get better when I turn the key or and restart the truck-and if I dont put it in park I can rev it all day.

Also Thought maybe a TPS issue but there are no codes.

The temps wear fine.
The overall ride was smooth.
No check engine lights.
No weird noises.
No smoking.
I thought I smelled bad fuel. Not sure.

Also since I got the truck if you rev the engine to different rpms and hold it the speed needle will jump around and stick in different places until you let off the pedal.

I need this truck right now…. Got a sick wife and babys and stuff.

Does anyone got any ideas?