Power drop....and then oil pressure drop when warm
 

I have a Ford F150 2005 5.4 Triton. I was getting an oil pressure drop when the truck got warm. so I change the oil in the filter and everything seemed ran fine for about 50 miles and then I lost power first and it sounded and felt like the catalytic converters were clogged but then as soon as that happened the the oil pressure droped all the way down and then i started hearing the lifters. is there something clogging the pickup tube? It acts like both of these problems come hand in hand. Like one is creating the other. Maybe oil pressure drop turns on the failsafe? Or is it like two problems at once? I haven't scanned yet so I don't know the codes. but then again 'm stuck out in the middle of nowhere with not an autozone around, only a McDonald's built right on the 44 turnpike in oklahoma...so I'm safe but I can really use somebody's input. And is there a pully assocciated with the oil pump? And if there is.... could it Be maybe binding up not spinning the oil pump fast enough?
ive read just about every thread on here....and though many are halfway like my problem... None are exactly like my problem...
Oh and by the way....iway....i have 312,000 original miles on this beast... And i was hoping to get at least 400,000.
( ran into a guy the other day that has 800,000 original miles on his old 1987 Ford F150)

UPDATE----

I made it about another old 25 miles or so down the road and I decided he's the oil pressure drop stopped so but but it still running rough like real rough losing power and everything so I decided to get underneath the truck here at oncue along 44 and lo and behold I have no catalytic converter somebody cut it off I bought this truck used while back never thought anything of it never thought to look under there for a caddy but yep it's gone there's a piece of pipe clamped in in its place so my next guess would be probably yeah plugs and stuff or all those other little things I hear everybody else talking about phasers and all that that's crazy with a phaser anyway you won't find a phaser on a freaking tree 1985 that's for sure more probably pre-1995 that's for sure when it comes to these when it comes to these new model trucks and cars I'm oblivious I have no idea what I'm doing the older models my dad and I used to build Motors all day long for his hobby stock I'm just out of curiosity if I do do a motor swap I heard the 5.0 was up pretty good butter anybody else have any suggestions I'd like a a bigger motor maybe a 351 Cleveland

Change the oil to 10w40 and see if that helps.

---update---
 

---after thought---
 

No, you have too low oil pressure and you are losing the passenger side cylinders would be my guess. The phaser is not working on that side due to the low oil pressure. The reason it runs well when cold is the oil is thicker and higher pressure. Put thicker oil in it or better yet install a melling high volume oil pump.

With that many miles, I'd do a full timing kit and an oil pump. This assumes the rest of the engine isn't excessively worn or sludged up.

Might be time to just cut your losses and get rid of it.

That's what the last owner did. That's how he ended up with the truck.