Ok, my truck was doing the SAME EXACT thing, I tried about everything you have, with no luck...

Had my cats "fixed" that didn't help, but I got way better throttle response.

SO...I was changing my oil, looking at my scheduled maintenance log, and Hmm, I am at 130k and the PCV valve has never been changed, so, 5 bucks on top of the oil, I throw it in.... OMG truck runs AWESOME!!!! My Idle went back to normal, I was blowing smoke at start-up, that's gone. Truck is getting way better MPG.

Seriously for 5 bucks, go bet a PCV valve and just replace the old one. It is INSANE how much that stupid, cheap little valve affects an engine. I am tickled beyond belief that my truck is back to normal, haha.

Good-luck I hope you get it fixed. Let us know if you try a PCV valve. And what the results are.

 

i have replaced my pcv valve within the past two months..

did some more tests today (bored)
vacuum, 23" hg at idle,
snap throttle
went to 2.5psi and then to 27" hg. which is great,
did a back pressure test,
fluctuated from below 0 to 0 (went off DPFE port so i was getting some of the scavenging effect of the manifolds)

everything i have checked comes out perfect...

but still just looking, i am going to look at my tb, iac, and egr this weekend when i have the time, to see if there is any extra build up in them, (mainly to see why my iac is at 40% on idle when spec is 20%-30%, maybe its a little clogged..)

but other than that, everything checks out great on my truck, so i am kinda stocked that the engine is showing all this great data,
i am beginning to believe the loss of power is just a fake perception i am making myself because i want it to be faster, and the fuel economy can just be the gas station i am currently filling up at (going to try another one next tank fill) (i go to the same station everytime)

 

Where do you get your gas? My truck lets me know that it doesn't like the cheap (well, poorly made) stuff... I would have thought that you would have noticed poor performance from gas selection long before doing all of these tests. My truck responds immediately to an inferior gas. I fill up at typical National Brand locations and I'll go out of my way every month or so to get some Shell gas... not that it's my personal feeling that it's better, but I think my truck likes the taste of it, bc it runs a bit smoother after a tank from there... Go Figure. Good luck diagnosing this, please keep us posted, bc if my truck starts doing this, I want to be able to find an answer...

 

i actually don't go cheap on my gas, i pay at the most expensive station most of the time, i go to the same shell every time that i need gas.. so i do go to a good national brand gas station... so thats why i really didn't think it could be the gas station at first...

i am thinking about trying the texaco next feel up (its just kinda out of the way) i was also thinking about running a tank of higher grade fuel, but i don't know if my wallet can take the hit, (it kills me paying $65-70 a week for fuel...)

 

From the PIDS you show, there is not even a minor problem.
If there are no codes set and all Monitors are satisfied, there is no problem.
Fuel mileage based on 15 miles is nowhere near enough to base fuel mileage on because of too many variables in such a short distance.
If the cats had an issue, the PCM would see it because the front and rear OX sensors would respond to the problem as well as the PID display would show it, it doesn't.
Both banks almost never show exactly the same on an older motor.
Injectors may not flow the same, cylinders are worn some etc.
Your trying to chase something that is not there.