1994 Ford Bronco idle spec problems

i have a 94' bronco w/ the 5.0 v8 that has a check engine light on. I had blown my head gasket and replaced the whole engine. After replacing the engine i had a check engine light on and the mechanic that replaced my motor told me it had to do w/ my idling too low while driving. I've since then moved my idle screw up and down each time taking it out for a drive to see if the light goes off. i've also removed my battery cables each time to reset it but much to my sorrow i've been unable to get the right spot. i was wondering if anyone would be able to help me