Tahoe Limited Problems Fuel filter??

[NX$paniard]

Well recently I have had a string of bad luck with my 2000 Tahoe Limited (5.7L Vortec 69,4xx miles))~~but only on long road trips. Initially I believed it was just clogged fuel filters... engine would not make power, rev high to maintain speed, and start to heat up, which when i replaced the fuel filter it seemed to fix the problems completely.. (was popping 4 OBD-II codes for all 4 O2 sensors- low voltages and a multiple misfire code). I still hear the fuel pump humming pretty good, but I thought it used to be louder (could be that I have more gas in it now?__not sure) but it does humm/ come on everytime i turn the key on and off and when I remote start the truck... As, I said, i was replacing fuel filters and everything would be great~~ untill recently, where the filter only last less than 2k miles, then the next one didnt even last 1k, then the next one only last 130 miles. I figured I had crap in my tank... so this last filter i put on seemed to cure everything it MADE IT OVER 1K MILES i made a 250 mile trip and everything went great, until I returned today....started doing the same thing, lack of power, high reving to maintain 60 mph, popped the 4 codes again, twice!!! So i swapped the filter on the side of the road as i was expecting this to happen.. didnt help.. Tahoe struggled all the way home for about 160 miles..i hate to drive it like that but whats my choice? So after it sat for a while, I go to start it up again after reading the codes and clearing them and it runs like normal again= i.e makes power shifts smoothly, etc.

What do you guru's think this could be??
is it just a lot of bad stuff in my tank (clogged filters, pump strainer?)?..
is my pump getting weak and gettin ready to crap out?
clogged injector/s? or just clogged filters?,
hell could it be BAD PLUG WIRES?????
Im also wondering if its only affected when it is used for long periods, because it only occurs half way into 200 mile + road trips, never in the city ??

as of now I think I will change plugs, wires, cap, rotor, and clean and re-oil my K&N to see what that does.. suprisingly enough the truck was actually doing really well on gas mileage even with these problems...
help me out fellas, itd be greatly appreciated!!
THANKS!!!