Just recently replaced cracked cylinder head on 2.3> Ranger...one with 8 plugs... head had just been magged, resurfaced and valve job. New gaskets and timing belt

Engine starts up and runs fine, but about 3-4 mins of idle it starts to idle up/down and sputter. If you throttle up it runs smooth. Was thinking IAC was going bad, the engine was being worked on for a cracked head leaking water and truck running very rough, had been run hot by owner.
I removed IAC and cleaned inside it and intake manifold(before reassembly), changed all associated gaskets in kit. While running it had a suck/hiss sound so I looked/felt for loose vacuum lines and such and then started to spray cleaner around all the "joints" to listen for engine change. As I come over some injectors it smoothed out. I removed everything to try to seal them up but to no avail. Even removed them, cleaned and replaced new o rings with new ones.

Now suck sound is less but engine will start to idle eratticaly after 3-4 mins... but upon driving truck runs good until stop with in gear, also trans wants to shift hard when putting in D, R from P.... Idle is below 1000 rpm
IAC ohms checks within range per a Ford book I have
Stumped.[]

 

my iac went bad my truck would sound like an elk but only at idle then rpm would go all over. changed that and rebuilt injectors