IDLE UP NOT WORKING AND LOWER THAN USUALL IDLE AFTER WARM UP

[aktive1]

HELLO, I AM A NEWBEE, THANKS AHEAD FOR ANY RESPONSES here is what i have done so far:
i have been having the same issue with my 99 ford 7.3. 122000 mi, for about 10 mths now, the idle up is not working, it seems like it tries but just will not kick in, so far in the last three weeks i have thrown about 500 bucks at this truck and still no answer and the more new items i have been installing the problem seems to get worse not better, i have changed the cps, ebp sensor, ait sensor yesterday morning, fresh oil and filter, checked turbo, (checked exhaust backpressure valve , i can move it by hand) new air cleaner, fuel filter, checked waste gate with 5-10 psi pressure works fine, also to make things worse sometimes it doesnt stay running till it gets warm and sometimes runs worse when warm unless i unplug either the new ebps or the icp sensor, today it was the Icp sensors turn, to keep it from bucking then stalling but i have not changed that yet. thats next...it is not leaking oil so i am not sure if its good or not.. this morning on the way to the shop it did the same thing no idle up, then erratic idle when warm almost to the point of stalling so i unplugged the ebps, idle was worse so i plugged that back in and unplugged the icp sensor, truck ran fine. has this happen to anyone and they were actually able to fix it without throwing several new parts at it? i scanned it about 6 times in the last 3 weeks and still keep getting the same codes relating back to the ebps and ebpv, 470- 475- 478, i have checked the hpop and the oil level is about 1/4 inch from the top, i have no leaks anywhere, any ideas where to look next, thanks