Fluctuating idle problems

[slmdrngr]

Does anybody know what causes the idle to fluctuate?, mine is anywhere from 717rpm to 904 rpm, before i changed the egr it got down to the mid 600's sometimes, this had been bothering me quite a bit, has anyone had these problems? I think its kinda weird, i wanna do the TPS mod, although i'm not getting any tps related codes, is there a way to adjust the idle on these explorers? 1996 auto 4.0 ohv 2x4

 

[slmdrngr]

UPdate

Ok, i think the problem may be with the IAC, i adjusted the idle with it unplugged, when warmed up, the tac says it is between 500 and 750 or so, o i have not hooked it up to anythig else to check rpms, but when i plug up the IAC it alsways idles up to 1000-1100 rpm, so i tried idling it down further than necessaru and when i plugged it back up, same result, tried unplugging the battery for ten minutes with it unplugged and after setting idle low, any help would be appreciated, im up to try anything for this now

 

[Explorer Junky]

Try the TPS(Throttle position sensor) Just had same issue on another vehicle. Thought it was IAC, replaced that, Didn't work. Then replaced TPS, and bingo bango, problem solved