My IACV is suspect for a rough idle.
Can one go out of spec and not throw a code?
I've cleaned it and tried to checked OHM's per FSM (kinda hard to get exact temps) although it opens and closes fine.
Also as I let off the throttle, it's kinda slow to idle down from 1000 to 700 rpm and when the idle drops, it's kinda rough.
I've checked for vacuum leaks (I've checked EVERYTHING several times), cleaned the throttle body and MAF, new factory plugs and wires, EGR is fine, new 02 sensors, TPS specs OK.
Oh, valves and compression is fine.
I've never stalled and overall the truck runs great, out but I feel the idle shouldn't be that choppy at 700rpm.
The only thing I haven't checked are the injectors but I don't think that's the prob.
Vehicle is a 97 4runner w/ a 2.7L and 5 spd w/ 98k.

 

Ive seen these 4 cyl motors have a rough idle and have compression check out ok and come to find out it had tight valves. Once the valves were adj, it ran perfect again.

 

I've checked the valves twice and all are within spec.