not to be a pain, but why would the IDLE air control valve be making his 3500-4500 range slugish?
anyhew, if you really want to clean it, it'* in the throttle body...
as for the reason your 3500-4500 is sluggish...
are you doing this while driving (sorry, i have to ask)? if this is in neutral, than your engine would be wise not to let you rev it that high. if it'* while you're driving, then we're opening up a can... of worms that is.
how long since the spark plugs themselves were done? you mentioned the wireset, but did you get the plugs while you were at it? when you say that the coil packs check out, do you mean you've swapped them with another car?
96 LeSabre (L36)
95 Olds LSS (L67)